Six-time champion Roger Federer cut a relieved figure after combatting the challenge of young pretender Alexander Zverev to seal his place in the semi-finals of the ATP Finals in London.
The 36-year-old Swiss powered through the final set at the O2 Arena to win the clash 7-6 (8-6), 5-7, 6-1 after being pegged back in the second by world No3 Zverev, who is 16 years his junior.
Federer reached the last four at the season-ending tournament for the 14th time and can have a stress-free showdown against Marin Cilic prior to Saturday’s knockout clash. Zverev can still qualify for the semis should he beat Jack Sock on Thursday.
“I’m happy and relieved that I can play freely against Cilic, instead of it being a nail-biter. It’s been a tough group so to be through in two matches is great,” said Federer.
“It was a good battle and I always enjoy myself at this beautiful arena. I have so much fun playing in London and I have been so successful here.”
Eighth seed Sock earlier beat Cilic of Croatia 5-7, 6-2, 7-6 (7-4) in the second round of matches in the Boris Becker Group.