LONDON, Nov. 15 -- Novak Djokovic edged fourth seed Milos Raonic after two tie-break wins to reach the semifinals of the ATP World Tour Finals in London's O2 Arena on Tuesday.
Djokovc, the second seed, beat the Wimbledon finalist from Canada 7-6 (6), 7-6 (5) in his second match of Group Ivan Lendl.
If Djokovic goes on to win the title, he will reclaim his year-end No. 1 in the ATP rankings from Britain's Andy Murray. The Serbian now has 11,180 points - 70 more points ahead of Murray (11,110), who will play his second round-robin match against Kei Nishikori of Japan on Wednesday.
Djokovic, who had been No. 1 for 122 consecutive weeks until November 7, will next play Gael Monfils of France.
"It was a very close match," said Djokovic. "I think very few points separated us tonight. It really could have gone either way. I was fortunate to get through the first set tie-break. I was down very early in both tie-breaks tonight. But I just managed to stay committed and put pressure on his second serves... Again, two tie-breaks against a big server is a great win and great confidence boost," he said.
In the day's other match, Dominic Thiem defeated Gael Monfils 6-3, 1-6, 6-4 to keep his dream of reaching the last final alive.
"It's very nice to get a win here... I was trying to stay tough in the third set," Thiem said. "I'm very happy with the win," he added.
Thiem will play his final round-robin contest against Raonic on Thursday.
