LONDON - Roger Federer bounced back to form and kept his chances of qualifying for the semifinals of the ATP finals alive with a convincing 6-2, 6-3 win over Dominic Thiem on Tuesday night in an hour and seven minutes.

If Federer looked bad-tempered and off his game in losing to Kai Nishikori on Sunday, Tuesday saw the return of the calm and controlled Federer, who was totally in control of his game.

The Swiss looked confident on his serve, winning 86 percent of the points on his first serve, while Thiem, who lost following two tie-breaks against Kevin Anderson at the weekend, was slightly off his best.

"It feels good and I am very happy, no game is easy here and I am not used to losing and coming back again, but it was a good challenge and I am happy with the way I played," said Federer after the match.

Federer said he had seen everything "negative" against Nishikori, "today I was more positive and I love playing in London. I remember what a privilege it is to play here," he commented.

Federer now needs to beat Anderson, who defeated him in Wimbledon, in order to assure a place in the last four.

"I am happy I am having a chance to play him again and I hope to get my revenge," he commented after beating Thiem.

Earlier in the day, Anderson blasted his way to a 6-0, 6-1 win over Kai Nishikori to claim his second win of the ATP Finals.

The South African, who had defeated Thiem on Sunday, needed less than an hour and five minutes to claim a hugely one-sided win, which he described as one of his "best ever".

Prior to the match, Anderson had promised to donate 100 US dollars for every ace he hit to firefighters combatting the current wildfires around Los Angeles (USA) and after hitting 10 aces in the match, he raised a total of 1,000 dollars.