Roger Federer moved one step closer to advancing to the semifinals of the 2014 ATP World Tour Final, while Andy Murray remained in contention for a spot in the final four.

Federer, who opened his campaign in the ATP World Tour Final with a straight-set win against Milos Raonic on Sunday, scored a 6-3, 6-2 win against Kei Nishikori to improve his chances of advancing to the next round.

Federer said that he expected a tough match against Nishikori, but the Japanese made it a lot easier for the second-seeded Swiss as he committed 30 unforced errors in the match.

"I was expecting a very difficult match," Federer said after the match via ESPN. "I've known him since he was 17 years old and always thought he was a great talent and he's going to have a great future."

Federer, who is still aiming to overtake Novak Djokovic in the year-end world rankings, managed to capitalize on Nishikori's costly errors, while also keeping his sheet clean with 17 winners against just 18 unforced errors.

"He took the important points, all the important points," Nishikori said via Sports Illustrated. "Maybe he didn't play maybe hundred percent, but all the tough points he played good serve, good points. He didn't give me a chance to come back."

With the win, Federer will advance to the semifinals unless Nishikori scores a very lopsided win in his upcoming match against Milos Raonic and Murray scores a blowout win against him on Thursday.

Murray opened his campaign with a disappointing 4-6, 4-6 loss to Nishikori on Sunday, but bounced back with a crucial 6-3, 7-5 victory against Raonic on Tuesday to the delight of the crowd inside the O2 Arena in London.

Murray needs to win against Federer in order to advance, but he could also earn a spot in the semis depending on the result of the match between Nishikori and Raonic.

"It depends on the winner of the Nishikori/Raonic match," Murray said of his chances of advancing to the semis via The Star Online. "If Kei wins, then I need to beat Roger, it depends on the scoreline of that match with Kei and Raonic. If Raonic wins, then I know that all I need to do is win the match against Roger and I'll be through."

Complete schedule of the 2014 ATP World Tour Final are available on this link, while highlights of matches can be seen here.