Serena Williams and Timea Bacsinszky reach French Open semi-finals

Serena Williams extended her unbeaten record against Sara Errani to nine matches

Top seed Serena Williams needed just 65 minutes to overcome Sara Errani 6-1 6-3 and book her place in the French Open semi-finals at Roland Garros.

The 33-year-old American, seeking her 20th Grand Slam title, proved too powerful for her Italian opponent.

Williams required just 27 minutes to take the first set but was made to work hard in the second by 17th-seed Errani.

She will face Switzerland's Timea Bacsinszky who beat Alison van Uytvanck of Belgium 6-4 7-5.

Williams, French Open winner in 2002 and 2013, hit 39 winners during a dominant display.

Timea Bacsinszky is the first Swiss woman since Martina Hingis in 2001 to reach the last four at Roland Garros

She had dropped the opening set in the previous three rounds but set the tone for a polished performance by breaking in Errani's first service game.

A fine backhand passing shot handed Errani, 28, an immediate break back but Williams cruised to the opening set.

Errani upped her pace in the second, but it was still not enough as Williams broke for a 4-3 lead and she finished it off on her fourth match point.

Williams remains on course for a 20th major singles title.

"I'm not putting too much pressure on myself... I'm surprised I'm still in the tournament, so this is really cool for me," she said.

Bacsinszky, 25, reached her first Grand Slam semi-final after overcoming unseeded Van Uytvanck, 21, in straight sets.

"For me, it doesn't matter who I'm going to be playing against," said Bacsinszky.

"I just want to have one or two or three tactics and try to put them in the game."