World number one Roger Federer brushed aside Fabrice Santoro 7-5, 6-4 on Friday to reach the semi-finals of the Toronto Masters in Toronto, Canada.

Defending champion Andy Roddick, the second seed, also went through with a 6-4, 6-2 triumph over Czech qualifier Jan Hernych.

Federer struck 47 winners as he racked up his 21st victory in a row, the longest sequence since Pete Sampras won 24 in 1999, to set up a clash with Thomas Johansson, who put out fellow Swede Joachim Johansson 6-3, 7-6.

The Wimbledon champion was confident going into the match against the 58th-ranked Santoro, having disposed of the Frenchman 6-1, 6-0, 6-2 when they last met in the Davis Cup.

But the feisty Santoro, four times a quarter-finalist in Canada, would not submit quietly on an overcast afternoon.

The opening set went with serve through five games, Federer leading 3-2, before the Swiss player seized control by breaking Santoro.

But Federer had difficulty closing out the set with Santoro, dubbed the 'Magician', breaking back at 5-4 and then holding to pull level at 5-5.

Federer, however, would not be denied and clinched the set on his fourth set point.

CLOSE AGAIN

It was close again in the second set until Federer earned the decisive break at 5-4 before holding serve to seal victory.

"It's very difficult to play against Fabrice, everybody knows that," Federer told reporters.

"I was playing with perhaps a little too much defence but I'm very happy with the way I'm playing," he said.

Roddick clinched a last-four showdown with Germany's Nicolas Kiefer, who rallied to down Austria's Jurgen Melzer 1-6, 6-3, 6-3.

It will be the American's third successive semi-final appearance in Canada.

"I should come up here more often," he said. "It's been very good to me."

Roddick was never threatened against the unheralded Hernych.

The first set was level at 3-3 before the American broke serve to snatch the initiative. He followed suit in the second set, breaking at 2-2 thanks to a powerful backhand.

"I felt like I hit the ball pretty well," said Roddick.