London: Novak Djokovic clinched another year-end No. 1 ranking and a semifinals berth in the ATP Finals with a comfortable win over Tomas Berdych on Friday.
Berdych was dispatched 6-2, 6-2 in a group match, giving Djokovic an unassailable points lead over second-ranked Roger Federer.
Djokovic, the Wimbledon champion, will finish the season No. 1 for the third time in four years. He's the seventh man to accomplish the feat at least three times.
"It's an incredible achievement. Being No. 1 in the world is one of the biggest challenges a tennis player can have," he said.
"I've been playing since I was four. I was very fortunate to have very knowledgeable people, people who believed in me, and believed in my talent."
Djokovic and Federer have swept their groups, and are on course to meet in Sunday's final.
Djokovic will take on Kei Nishikori in the semifinals at the O2 Arena, wile Federer will face his Davis Cup teammate Stan Wawrinka or U.S. Open champion Marin Cilic, who met late Friday.
Djokovic extended his two-year-old indoor winning streak to 30 matches. The two-time defending champion in London, he has lost only nine games this week.
Berdych dropped his first two service games as the Serb took control from the baseline. Djokovic again broke twice in the second set with a range of forehand winners, strong returns and net charges that left Berdych stranded frequently.
"There was not much doubt that the match could go the other way," Berdych said. "There was no way I can challenge him better than this."
Beside winning his seventh Grand Slam title at the All England Club, Djokovic was also runner-up at the French Open, and won six titles. He has been in supreme form since the birth of his first child, Stefan, on Oct. 21, and won 16 of his last 17 matches.