Lendl

In modern professional tennis, winning a big tournament is considered a greater achievement than winning several smaller tournaments of the same combined value. Hence, top players typically concentrate on bigger tournaments and only play a few smaller ones in between. Consequently, top players play and win fewer matches than before. Since Ivan Lendl won 106 out of 115 matches he played in 1982, nobody won more than 90 matches in a single season, except Roger Federer, who went 92-5 in 2006.