Sometimes when someone does something so unprecedented, the achievement fails to get the deserved recognition, because there is nothing to compare it to. When Novak Djokovic won four majors in a row on three different surfaces, the achievement was overlooked. There was nothing to compare with what Djokovic had done. Some tried to compare it to things Roger Federer had done, but Federer never won four in a row. Others wanted to compare it to Rod Laver's grand slams, but that was on only two different surfaces
Zverev's incredible run to the title in Rome has been compared to other players from outside the Big Four winning Masters Series 1000 titles, but none of those players were 20-years old at the time. The next youngest players to win a Masters Series 1000 title in the era of the Big Four aren't even close to Zverev.
23-year old Jo-Wilfried Tsonga: Paris (2008)
24-year old Tommy Robredo: Hamburg (2006)
25-year old David Nalbandian: Madrid & Paris (2007)
26-year old Robin Soderling: Paris (2010)
27-year old Marin Cilic: Cincinnati (2016)
A lot has changed in tennis in the nine years since Tsonga won the title in Paris. The most impressive stat to come out of Sunday's final was that Sascha, born in 1997, was the first player born in the 1990's to even win a set in a Masters Series final. That is an entire generation of players that got skipped.
This graph gives a visual representation of the distribution of Masters Series 1000 titles by birth year with the red bar all alone on the right belonging to Zverev.
Below is a list of all the players who at the time of their first title were the youngest to have won a Masters Series 1000.
Stefan Edberg (1-19-1966) - won the first Masters Series 1000 tournament
Andre Agassi (4-29-1970)
Michael Chang (2-22-1972)
Andriy Medvedev (8-31-1974)
Roberto Carretero (8-30-1975)
Marcelo Rios (11-11-1975)
Carlos Moya (8-27-1976)
Mark Philippoussis (11-7-1976)
Marat Safin (1-27-1980)
Lleyton Hewitt (2-24-1981)
Roger Federer (9-8-1981)
Guillermo Coria (1-18-1982)
Andy Roddick (8-30-1982)
Rafael Nadal (6-3-1986)
Novak Djokovic (5-22-1987)
Marin Cilic (9-28-1988)
Alexander Zverev (4-20-1997)
This means that with his title in Rome, Sascha broke a new record by being 3,126 days younger than the next youngest player with a Masters Series 1000 title. It is actually twice as big of a gap as any two other players on the above timeline.
The second largest gap was the time between the birthdays of Edberg and Agassi. However, both of these players won their first Masters Series titles in the first year of the event. If Masters Series 1000's had been played before during the 1980s, certainly someone born between those two dates (like a Boris Becker or Thomas Muster) would have already won a title.
Here's how many days younger each player is than the next youngest player to have won a 1000 at the time of their first title.
This stat gives an indication of just how hard it was to break through at the time of their breakthrough. In other words, Coria, Rios, Philippoussis and Federer broke through at a time when there was a vacancy at the top of the game. Since this is Big Four era, it's no surprise that it has never been harder to do what Zverev just did this week in Rome.