BASEL (Reuters) - Roger Federer was stretched to the limit by Gilles Simon before overcoming the valiant Frenchman 7-6(1) 4-6 6-4 to reach the semi-finals of his hometown Swiss Indoors tournament on Friday.
The Swiss needed 2-1/2 hours to finally break his opponent's resistance as he claimed his 18th successive win at the tournament, which he is aiming to win for the ninth time.
There was an early warning when Simon broke in the second game and raced to a 5-2 lead. World number three Federer fought back to 5-5, then saved a set point in the 12th game before winning 7-1 in the tiebreak.
The second set produced five breaks of serve -- three to Simon and two to Federer -- before the Frenchman, ranked 32nd, held serve in the 10th game to level the match at 1-1.
Federer broke in the second game of the final set but Simon refused to give in and replied in the seventh. But he finally lost his nerve in the 12th game when two unforced errors in a row handed Federer the match.
"I knew it was going to be difficult... I was a bit unsure of my serve and his return is excellent," said Federer.
Second seed Alexander Zverev also went through with a 7-5 6-3 win over Roberto Bautista Agut, his 52nd win of the year.
The world number five is aiming for his fourth ATP title of the season.
Qualifier Marius Copil, who beat third seed Marin Cilic in the second round, continued his run with a 7-6(6) 7-5 win over American Taylor Fritz.
Still to drop a set, the Romanian hit 18 aces and saved 10 of the 11 break points he faced in a match lasting nearly two hours.
(Writing by Brian Homewood, editing by Pritha Sarkar)