Most Semifinals at Single Tournament

At the top of the Open Era list for Most Semifinals at a Single Tournament stands Roger Federer, who reached the semifinals of Basel / Swiss Indoors 16 times — the highest known men’s singles total at one tour-level event. Federer also reached the semifinals 16 times at the ATP Finals. He reached a record 15 Basel finals and also lost in the 2002 Basel semifinal to David Nalbandian, giving him 16 total semifinal-or-better appearances at his hometown tournament.

Behind him, the strongest Grand Slam benchmarks are Rafael Nadal at Roland Garros and Roger Federer at the Australian Open, both with 15 semifinals. Nadal went 14-1 in Roland Garros semifinals and ultimately won 14 titles there.

Another tour-level reference is Roger Federer at Halle, where he reached the semifinals 15 times, while the Masters 1000 benchmark is Monte-Carlo, where Nadal reached the semifinals 14 times.

In this record, the milestone is not simply winning the title, but repeatedly surviving to the final four at the same event: Roger Federer set the overall single-tournament ceiling with 16 Basel semifinals, Nadal and Federer share the Grand Slam version with 15 semifinals at Roland Garros and the Australian Open, and Monte-Carlo provides the Masters 1000 benchmark through Nadal.