Lethal Federer cuts down Dimitrov

Federer, a five-time champion in the city of his birth, played a second-set tiebreaker to perfection against the 22-year-old. Seventeen-time major winner Federer also strengthened his position for a place in the eight-man World Tour Finals starting in London in 10 days.

He stands provisional seventh as he heads into a Saturday semi-final with Canadian Vasek Pospisil, who beat Ivan Dodig 7-6 (13/11), 6-4. Federer could qualify for London if he wins a sixth title in Basel on Sunday, according to ATP calculations.

The Swiss great improved his record to 18-1 against players born in the 1990s, with his only loss in that category coming in Hamburg against Argentine Federico Delbonis this year. Federer was pleased to be finding some consistent from after one of the poorest seasons of his career.

He began with a wobble on Friday and was forced to save five break points in his opening service game against the Stockholm champion from last week. "It was very important to win in two sets," said Federer. "There were a lot of free gifts out there in some games.

"When I saved three set points (second set) I just told myself to play one point at a time and hope to get there. I broke him (for 5-5) and that made it difficult for him. I was able to come through well in the tiebreaker.

"It always feels good to win at home," added Federer, whose lone title so far came in the summer in Halle. Top seed Juan Martin del Potro won his 300th career match as he marched into the semi-finals with a 6-4, 6-4 win over Paul-Henri Mathieu.

The top seed and defending champion crushed the French qualifier in 78 minutes and will next face a second French opponent after Edouard Roger-Vasselin beat Germany's Daniel Brands 6-3, 4-6, 6-3.

"I played a good match," said the South American, who sent down 11 aces and never faced a break point. "I was solid from the baseline and served well. I've been working a lot of my serve," added the Tokyo tournament champion and Shanghai finalist from earlier this month. "I'm playing better and better with each match.

"I did have a double-fault so I still have a little work to do. I'm looking forward to tomorrow and I'll have to lift my level even more."

Del Potro, already qualified for the World Tour Finals, owns a record of 46 wins and 13 losses in 2013, winning three titles.

Unseeded Canadian Pospisil reached his third semi-final of the season -- and the third of his career -- as he played after treatment for a stiff neck which had him doubting if he could take to the court. But the number 40 managed with physiotherapy and painkillers, beating Croatian Ivan Dodig 7-6 (13/11), 6-4.

"I honestly didn't know if I'd be able to play at all," said the Canadian. "It was still bothering me on every single shot, especially the serve and forehand. But the trainer told me I couldn't make it worse so I gave everything I had."