Djokovic clinches ATP year-end No. 1, Wawrinka moves on to semis

For the third time in four years, Novak Djokovic will finish the ATP season ranked No. 1 after his win over Tomas Berdych at the ATP World Tour Finals on Friday. Stan Wawrinka defeated Marin Cilic to earn his spot in the semifinals.

LONDON -- For the third time in four years, Novak Djokovic will finish the ATP season ranked No. 1. Djokovic took over the top ranking from Rafael Nadal by winning his second Wimbledon title this summer and clinched the year-end No. 1 ranking after he beat Tomas Berdych 6-2, 6-2 on Friday to go undefeated in Group A play at the ATP World Tour Finals. With the win, the two-time ATP Finals defending champion qualified for the semifinals for the third consecutive year and will play No. 5 Kei Nishikori on Saturday afternoon. Stan Wawrinka qualified for his second straight semifinals after beating Marin Cilic 6-3, 4-6, 6-3 to set up an all-Swiss derby against Roger Federer on Saturday night. 

Wawrinka will play Federer in the semifinals on Saturday :: Julian Finney/Getty Images

It was yet another dominant performance from Djokovic, who extended his indoor win streak to 30 consecutive matches. He has blew through the Group A field, losing just nine games in three matches. The scorelines in those matches were as follows: 6-1, 6-1, 6-3, 6-0, 6-2, 6-2, with four of those sets (including two breadsticks and a bagel) coming against the two reigning hard court Slam champions, Marin Cilic and Stan Wawrinka.

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In their only match of the season before today, Berdych narrowly avoided a double-bagel when Djokovic beat him 6-0, 6-2 in the China Open final. The Czech, who will finish the season at No. 7, fared only slightly better on Friday. Clean and precise of the ground, Djokovic finished with 18 winners to 10 unforced errors, while Berdych hit 8 winners to 19 unforced errors. Holding serve has proven difficult for the game's big hitters this tournament and that proved true once again for Berdych, who won just 30 percent of his second serve points against the game's best returner. The difficulty of earning cheap points on serve has turned the tournament into a baseliner's mecca, with the surface rewarding consistency off the ground as opposed to outright power.

"I find the court very tricky, very challenging," Berdych said. "It doesn't allow you for any mistakes. In my word, I think it's very slow. You know, for us who wants to hit the serve and try to play aggressive, it's very difficult."

Djokovic, Berdych win easily as more questions are raised in London

Djokovic is aiming to become the first player in nearly 30 years to win the year-end championships three times in a row. Ivan Lendl was the last man to accomplish the feat from 1985 to 1987. His last loss at the tournament came in 2011, to Janko Tipsarevic, and he's currently riding a 12-match win streak at the O2 Arena. He has less than 24 hours to rest and recover for the semifinal against Nishikori. The two have split their four matches, including their two matches this season and Saturday's matchup will be the second time they square off since Nishikori upset the Serb in the U.S. Open semifinals. Just two weeks ago on the indoor court in Bercy, Djokovic beat Nishikori 6-2, 6-3. 

This post will be updated.