Federer needed two hours to beat Monfils 6-0 4-6 7-6 in a dramatic match on Court Manolo Santana.
Not only did it put Federer into the quarters, but it also clinched his 1,200th career win.
And he is now just 74 behind leader Jimmy Connors.
Of the current generation of ATP stars, Rafael Nadal is fifth on the list with 936 while Novak Djokovic has 853.
Federer’s first win came against Guillaume Raoux in 1998, his 500th was a victory over David Ferrer at the Monte-Carlo Masters.
And the 1000th came in 2015 to win the Brisbane International.
758 of Federer’s wins have come on hard courts while 914 have been outdoor.
Ivan Lendl, who is third on the list with 1,068 wins, told the ATP: “Winning so many matches and being consistent for so many years is a by-product of preparing and working hard.
You won’t always play well, but you find a way to win. It also takes good coaches and trainers, which Federer has had, to achieve these feats.”