Top 20 Under 20

Just a few weeks after 19-year old Australian Nick Kyrgios reached the Wimbledon quarterfinals, 17-year old German Alexander Zverev reached the quarterfinals at Hamburg today. After the pair of impressive runs by the teenagers, I decided to take a look at the other promising teenagers in tennis right now. This is my list of the 20 most promising talents in tennis that are under 20 years old. The only other requirement to be on this list is that the player has a current ATP ranking.

1. Nick Kyrgios (AUS) 19-years old, No. 66 -- Just a couple weeks ago, Kyrgios soared to a new career-high ranking of No. 66 after he defeated world No. 1 Rafael Nadal to reach the Wimbledon quarterfinals. His win over Nadal gave him a 12-match win streak on grass going back to his triumph at the Nottingham Challenger, where he had to go through qualifying. That title was what allowed him to reach the main draw at Wimbledon. In 2013, junior No. 1 Kyrgios won the Australian Open juniors title without dropping a set and then earned his first tour level victory with a straight sets win over Radek Stepanek at Roland Garros.

2. Alexander Zverev (GER) 17-years old, No. 285 -- With his win over Santiago Giraldo today, Zverev will crack the top 200 for the first time in his career. He will be two years younger than the second youngest player in the top 200 when the rankings come out on Monday. The former junior No. 1 started the year with a 12-match winning streak, which included an Australian Open title before starting his transition to the senior tour. During the second week of Wimbledon, Zverev won his first challenger title in Braunschweig, defeating Kamke, Souza, Golubev, and Mathieu, who have 375 career wins combined, including 21 this year on the tour level.

3. Borna Coric (CRO) 17-years old, No. 232 -- Coric earned his first tour-level victory of his career earlier this year with a five-set win over world No. 21 Jerzy Janowicz in Davis Cup. It remains the only tour-level victory for the Croat, who has had most of his success in juniors and at the futures level. Coric has won five futures titles, including three in a row at the tail end of his 2013 season. He was just 16-years old when he earned the No. 1 juniors ranking. He won the 2013 juniors US Open, which included a win over Zverev in the semifinals.

4. Andrey Rublev (RUS) 16-years old, No. 454 -- The current junior No. 1 claimed the boy's singles title at Roland Garros this year. Rublev defeated Zverev in Canada, but the German got him back in the Orange Bowl to end the 2013 season. Rublev has reached four futures finals in the last 12 months and won three of them to push his ranking inside the top 500.

5. Christian Garin (CHI) 18-years old, No. 346 -- Garin has already made a name for himself in Davis Cup with three wins in the last 12 months. The Chilean also defeated Dusan Lajovic in the first round of his home tournament in Vina del Mar in 2013 for his only main draw tour victory. Garin has notched two futures titles and four finals along with seven main draw victories at the challenger level. Garin also defeated countryman Nicolas Jarry twice on clay this year. At the US Open boy's singles event last year, he defeated Jared Donaldson, Ymer Elias, and Johan Sebastian Tatlot before falling to Thanasi Kokkinakis in the semifinals. Earlier that year, he defeated Zverev in the Roland Garros final after wins over Coric and Laslo Djere.

6. Jared Donaldson (USA) 17-years old, No. 343 -- Donaldson may have lost to Garin twice in juniors, but the American is the one with more futures titles and a better ranking despite being a year younger. Donaldson won his first challenger match earlier this week, defeated world No. 160 Marius Copil 7-5, 6-1 in Binghampton. That win pushed Donaldson's winning streak to 16 matches, following his three consecutive futures titles. The first of which came in Turkey, where he beat Nikola Milojevic in straight sets in the final. In fact, during the winning streak, Donaldson dropped just two sets in total and the most games in he lost in any set of the Turkey F19 was just four. The 17-year old has also beaten Laslo Djere twice this year already.

7. Francis Tiafoe (USA) 16-years old, No. 1134 -- Tiafoe is the lowest ranked player on this list, but at not even 16-years and 6-months old, the American is already getting plenty of attention. Tiafoe is currently ranked No. 6 in the juniors rankings, but was as high as No. 2 just a few months ago. Tiafoe has won both the Easter Bowl and Orange Bowl in the last 12 months. All of his experience on the senior tour has been just four futures events in the United States and one in Spain, where he has reached three quarterfinals.

8. Thanasi Kokkinakis (AUS) 18-years old, No. 298 -- The 18-year old Australian started the year with just one week spent inside the top 600, but just a month ago, cracked the top 300 for the first time. Kokkinakis got his first tour-level victory this year with a win over Igor Sijsling at the Australian Open before he had to face Rafael Nadal. Kokkinakis has twice been a runner-up at junior majors. In the 2013 Australian Open, he lost in the final to Nick Kyrgios, who was his doubles partner as they won the boy's doubles title at that event. At the US Open final, he lost in three sets to Coric. En route to the two finals, he claimed wins over Nicolas Jarry, Coric, Garin, and Gianluigi Quinzi in both.

9. Nikola Milojevic (SRB) 19-years old, No. 457 -- The Serb got his first tour-level victory in Dusseldorf earlier this year with a three-set win over Mirza Basic before losing to eventual finalist Ivo Karlovic. Milojevic has won two futures events in the past 12 months and reached the final of three. In January 2013, Milojevic became the No. 1 junior in the world. Milojevic won the Abierto Juvenil Mexicano, which is a Grade A juniors tournament.

10. Stefan Kozlov (USA) 16-years old, No. 862 -- At Wimbledon this year, Kozlov took home the runner-up trophy for both boy's singles and doubles. It was his second runner-up finish at a junior slam, and he is still just 16, which is why he is even higher on many other people's lists. Also, he has notched wins over several of his peers on this list, including Zverev, Tiafoe, Johan Sebastien Tatlot, Hyeon Chung, Rublev, and Milojevic all in the last year on the junior tour. Still, he has only reached one futures semifinal, which he lost in straight sets. He has also been the victim of many upsets in his career as a junior.

11. Hyeon Chung (KOR) 18-years old, No. 252 -- Chung never spent much time on the junior circuit peaking at a ranking of No. 7, but that hasn't hindered him from tearing it up on the hard courts of the senior tour. Chung already has acquired four hard court futures titles and seven finals, including three titles in five finals in 2014. He also has a record of 6-3 on hard courts in the challenger tour. Chung may never develope into an even halfway decent dirtballer, but he could still do some damage on the tour level, over half of which is played on hard courts. Chung has already reached the semifinals of two challenger events this year and is inside the top 200 for the Race Rankings.

12. Noah Rubin (USA) 18-years old, No. 532 -- His ranking of 532 is only one spot better than the worst on this list of anyone older than 16, but Rubin's ranking doesn't truly reflect his potential. Just a couple weeks ago, Rubin bagged the boy's singles title at Wimbledon after coming through qualifying and then beating both Tiafoe and Kozlov. Rubin plays well on all surfaces and even had a win on carpet this year. Along with his Wimbledon title, he has 15 wins on hard courts and 13 on clay. Rubin started the year ranked 767 and his ranking will continue to rise as he continues to play futures events in Europe instead of at home.

13. Kyle Edmund (GBR) 19-years old, No. 275 -- Other than Kyrgios and Zverev, Edmund has amassed the most impressive results in his career on the senior tour. The only reason he falls so low on the list is because of his age. Edmund still hasn't cracked the top 250 despite winning four titles on clay and one on hard courts at the futures level. Edmund has even gone 7-6 this year on the challenger tour to go along with his impressive 17-3 record in the futures. He has notched wins over Dustin Brown, Go Soeda, and Aljaz Bedene, who bounce back and forth between the tour level and challenger level.

14. Gianluigi Quinzi (ITA) 18-years old, No. 301 -- The former junior No. 1 was the 2013 Wimbledon boy's singles champion, but it has been on the clay where he has done the most damage. He is 17-1 on clay this year with three titles at the futures level. However, his Nadal-like numbers on clay haven't translated well to the challenger tour, where he is just 1-3 this year and 8-18 in all challenger matches. However, his one win in challengers this year was against Nicolas Jarry.

15. Roman Safiullin (RUS) 16-years old, No. 682 -- Safiullin won the Italian Open in his most recent event, defeating Rublev in the final 6-2, 6-3. In the Russian's first event on the senior tour earlier this year he won the Uzbekistan F1 title, which included a win over 27-year old Denys Molchanov, who is now ranked 213 in the world. Safiullin has since reached the quarterfinals once and semifinals twice at his other three futures events. Safiullin has already been as high as No. 2 in the junior rankings.

16. Yunseong Chung (KOR) 16-years old, No. 994 -- Chung, the youngest player on the list, won the 2013 under 16 Orange Bowl and has now reached a junior ranking of 25. Chung has only played three tournaments on the senior tour and already has cracked the top 1000. Chung reached the final of the Korea F6. At the boy's singles event at Wimbledon, he was knocked out in the second round by Tiafoe. That was his only official match against anyone else on this list in the last 12 months.

17. Elias Ymer (SWE) 18-years old, No. 281 -- Ymer got as high as No. 5 in the juniors rankings. Rubin is the only player on this list that he has beaten on the junior tour, while losing to Laslo Djere twice, while losing to Zverev, Garin, and Edmund once each. Ymer got his first tour-level main draw victory last week in Bastad, beating Mikhail Kukushkin. He has also won five futures events in four different countries already this year. Ymer has been on fire since the start of March, meaning he has a great chance to see his ranking take a boost between now and March 2015.

18. Laslo Djere (SRB) 19-years old, No. 347 -- Djere has played exclusively on the futures tour this year and has collected two titles, which both came on clay where he has a record of 25-7. Djere's most impressive win this year was over 20-year old No. 277 Jordan Thompson en route to his first title of the year. In 2012, Djere won the Orange Bowl, defeating Quinzi and Ymer along the way as he brought his junior ranking to a career-best No. 3.

19. Johan Sebastien Tatlot (FRA) 18-years old, No. 533 -- Tatlot was the only players not representing the United States to reach the Wimbledon semifinals at the junior tournament. Tatlot is currently the No. 8 junior in the world and has been as high as No. 5. Tatlot also reached the semifinals at the Orange Bowl, where he lost to Tiafoe. Tatlot has gone 15-8 on clay at futures tournaments this year and has reached one final. He has a record of 1-2 in futures finals in his career.

20. Nicolas Jarry (CHI) 18-year old, No. 332 -- The former No. 8 junior's accomplishments have been overshadowed by his countryman Garin, but his clay court ability has earned him a spot on the list. He defeated both Garin and Hyeon Chung in Canada last year before falling in the final. Jarry has an incredible 33-8 record on the clay in futures events and has reached six finals with two titles in 2014. Jarry is as high as No. 226 in the Race Rankings thanks to his 26-4 record since the start of May. However, three of those losses came to fellow teenagers and he only has one main-draw win on hard courts on the senior tour. Still, by May 2015, Jarry could be well inside the top 200 of the world.