Roger Federer was forced to dig deep and repel a couple of John Isner match points to move Team Europe a step closer to defending their Laver Cup title in Chicago.
In a tournament which has exceeded all expectations, 20-time Grand Slam champion Federer shrugged off the disappointment of doubles defeat to down Isner 6-7 (5-7) 7-6 (8-6) 10-7 at a packed United Center on Sunday.
Federer's win left Europe on the brink of victory with a 10-8 advantage with two more singles rubbers left to play.
One victory would be enough to see Europe retain the crown they won at the inaugural event in Prague last year.
Sock and Isner win epic doubles
"I'm not sure I wanted (this tournament) to be that exciting," said 37-year-old Federer. "What a match, what a weekend. Thank you Chicago. Regardless of what happens, it's been a successful weekend and we've loved every minute here. I think I can speak on behalf of all the players.
"The Laver Cup was an idea to celebrate tennis and to have a great weekend and I think we've had that. It's been terrific throughout."
The giant American won a tight opening set after successfully landing with a cross-court forehand winner before Swiss world No 2 Federer saved a match point with a stunning backhand winner to bring up another tie-breaker.
After saving a second match point with an unreturnable angled return, Federer landed an ace to send the match into a Super tie-break.
This time Federer took control from the start and he went on to win an enthralling battle when his dipping forehand landed plum in the corner before Team Europe - including captain Bjorn Born - celebrated with push-ups.
The beautiful lakeside city of Geneva will host the next Laver Cup from September 20-22, 2019.
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