Roger Federer came from behind to defeat Denis Istomin 4-6, 6-3, 6-2 and progress to the quarter-finals of the Swiss Indoors in Basel.
The third-seed mounted a spirited fightback in front of his home crowd after conceding the first set to the little-known Uzbek.
Federer was required to dig deep to save four break points during an eight-minute marathon game at 1-1 in the third and final set.
The 32-year-old fought hard for just under two hours to book a place in the last-eight, and cited his relatively sub-par performance as a necessary wake-up call.
"I stared poorly, making too many errors, especially on the forehand,'' said Federer.
"I was risking too much and it was not paying off. I had to cut that risk and was a bit lucky to win. I started fighting back and got better as the match went on.
"I'm happy that I was able to turn it around, I needed a match like this.''
Currently ranked seventh in the world rankings, Federer's victory grants a welcome boost to his hopes of qualifying for the eight-man season-ending ATP World Tour Finals in London next month.
However, the remainder of his tournament in Basel and the upcoming Paris Masters will be the most crucial events towards shaping the tail-end of his campaign.
Novak Djokovic, Rafael Nadal, Juan Martin Del Potro, David Ferrer and Tomas Berdych have already booked their places at the event at the O2 Arena in London, although Andy Murray has been forced to withdraw through injury.
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