Rafael Nadal ushered Stanislas Wawrinka into the semi-finals of the World Tour Finals on Friday as the world number one Spaniard and the Swiss both posted final group victories to reach the weekend final four.

Nadal’s defeat of Czech Tomas Berdych 6-4, 1-6, 6-3 in just under two hours sent Wawrinka ahead to join Nadal and world number two Novak Djokovic at the business end of the year-end event. Wawrinka beat Spain’s David Ferrer 6-7 (3-7), 6-4, 6-1.

Six-time champion Roger Federer and Argentine Juan Del Potro will duel for the final spot in the semis on Saturday.

Nadal, who will finish the season as the world number one for the third time in his career, is in the chase for a first year-end title, one of the few honours he has never claimed.

Nadal beat Berdych for the fifth time this season to now stand 74-6 in 2013. Berdych is the only member of the top 10 without a title this season.

Wawrinka’s fighting comeback took two hours, 18 minutes to advance the Swiss during what has been a breakthrough campaign.

“It’s amazing week for me already. I beat Berdych, number five David Ferrer, I lost a tough one against Nadal. It was quite good level for me, that’s the most important,” said Wawrinka, who led Ferrer in the opening set 5-2, but tossed out his chances and ended up losing it in a tiebreaker after more than an hour on court.

“I can be only really happy with the tournament.” Wawrinka committed 30 unforced errors in the disastrous first set, but cleaned up his game remarkably, as his victory in the second set provoked a rare racquet smash from Ferrer.

Wawrinka quickly earned two breaks in the final set and rode the momentum to a win, ending with 35 winners, 56 unforced errors and conversions on six of seven break points.

“I saw at the beginning that he’s not really at his best,” said Wawrinka. “He’s a little bit tired, especially mentally. Every long rally, I had the control of it.

“The important thing was to fight with myself to keep the ball in, to try to stay with him, to show him that I’m gonna play some long rallies, that I’m going to try to be aggressive, but not rushing too much.

“That’s what I did better at the end and it made a big difference today,” Ferrer said.

“I was showing him that I’m gonna be there and I’m gonna improve my game if I can, I’m gonna fight on every ball. That if he wants to beat me, he has to really find the way to beat me.”

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