Grigor Dimitrov cruises, David Goffin will play Roger Federer

Grigor Dimitrov defeated Pablo Carreno Busta with a crushing 6-1, 6-1 victory. Julian Finney/Getty Images

LONDON -- Grigor Dimitrov had already qualified for Saturday's ATP Finals semifinal when he stepped out onto court on Friday, but that didn't prevent him from blowing Pablo Carreno Busta off the court with a crushing 6-1, 6-1 victory.

There had been concerns that -- what with the late night scheduling of this game ahead of his Saturday semifinal against Jack Sock-- the Bulgarian may tire himself out. But with the game lasting a succinct 60 minutes, there was little danger.

In spite of the overwhelming score line, Carreno Busta didn't actually play badly, but instead, all credit to Dimitrov who displayed a near-perfect performance.

If Dimitrov continues in this form it will be hard for Sock to challenge him, despite the American winning three of their four previous encounters.

On the opposite side of the draw, fates was hung upon the result of Dominic Thiem's matchup with David Goffin.

Neither Thiem nor Goffin had had an impressive run thus far in the tournament, but Friday was the day to make it count; the winner would progress to the semifinals on Saturday, while the loser would go home.

After Goffin's absent Wednesday evening performance, Thiem was the marginal favourite. But the Belgian -- still with heavily strapped left knee -- fought to a straight sets 6-4, 6-1 victory.

"It was difficult to play against Dominic, such a close friend and such a nice guy. But in the end, I was really happy about the way I played the match, I was really nervous towards the end of the match," Goffin said in his on court interview after the match.

Goffin had a shaky start; resembling his terrible 6-0, 6-2 Wednesday loss to Grigor Dimitrov. His unforced errors were flying all over the court and Thiem snatched an easy break and quickly led 3-0.

Thiem, though -- also on a recent run of bad form -- was delivering his share of mindless errors; one particularly mistimed backhand fired off the frame and well up into the stands, and was met with a pantomime 'ooh' from the crowds. Five games on the trot and Goffin had turned the score around to 5-3, before claiming the first set 6-4 with a whipping forehand down the line.

Thiem then received a medical timeout for a left knee problem.

From then on, the young Austrian seemed unable to really get his racket back in the game: he conceded two more early breaks and allowed his opponent a 4-1 lead in the second. Four break points for Thiem in the sixth, but a string of wild backhands allowed Goffin to claim the game before Goffin closed in on the final set 6-1.

Goffin will play Roger Federer in the semifinals on Saturday; when the pair last met, at the Swiss Indoors last month, Goffin only managed to claim three games from the World No.2.

"I've never found a key to beat Roger," Goffin said after defeating Thiem on Friday.

"Honestly, I don't know what to do tomorrow. But I'm going to try something, something different, something that I've never done in the past. In Basel, it was not easy. He played well. He didn't miss. He was really aggressive, as always. He returned so well. So it was not easy in Basel.

"I hope that tomorrow he's not going to play the same match. But I will try something different for sure, yeah."