LONDON - Alexander Zverev set up a semifinal with six-time champion Roger Federer by defeating John Isner 7-6 (7-5), 6-3 on Friday.
Zverev is the youngest player at 21 to reach the semifinals since 2009 and the first from Germany since 2003.
The 37-year-old Federer holds a 3-2 career record over Zverev.
Isner and Marin Cilic, who later lost 7-6 (9-7), 6-2 in a dead rubber against group winner Novak Djokovic, were eliminated by the result.
Five-time champion Djokovic was to face debutant Kevin Anderson in the other semifinal on Saturday.