Grigor Dimitrov savors the moment after beating David Goffin 6-0, 6-2 to reach the semifinals of the ATP World Tour Finals on Wednesday. HANNAH MCKAY/REUTERS

LONDON - The coaching seemed to have helped, whether Grigor Dimitrov heard it or not.

The sixth-seeded Bulgarian made his way into the semifinals of the ATP World Tour Finals on Wednesday by whipping David Goffin 6-0, 6-2, but was given a violation for coaching during the second set.

A linesman informed the chair umpire of the infraction during the fifth game of the final set, and Dimitrov reacted by saying he didn't hear anything.

He probably didn't need any extra advice anyway, not after the way he was playing, and the way Goffin was, too.

"Yeah, that was very weird, to be honest," Dimitrov said of the violation. "I have no idea why. But it's fine ... I mean, when you're so zoomed into the match, you don't even pay attention to all that."

Dimitrov ended up winning 34 of the 47 points he served and won 32 of the 57 points served by Goffin.

In the first set, Dimitrov lost only two points on his serve and twice broke Goffin without even going to deuce.

Goffin finally managed to hold serve in the second set, but Dimitrov still was able to break the Belgian's serve twice more.

"I was just following my game. Just as simple as that," Dimitrov said. "I was using every opportunity. I took care of all of the balls that I had to."

And he gave Goffin few chances to make a comeback.

"He came to the net from the beginning, from the first point," Goffin said. "It was not easy for me to lose my serve from the start. It was tough for my confidence after that when it was 0-4."

Dimitrov had won three of his four previous meetings with Goffin and was quick to establish control once again.

Goffin had a wrap around his left knee and Dimitrov immediately tested his mobility, moving his opponent around the court with some deft groundstrokes and landing an early blow with a break in the second game of the first set.

Dimitrov dominated from the baseline, breaking twice more to take the set in just 27 minutes, and carried his dominance into the second set, racing into a 3-0 lead after winning nine games in a row.

The Belgian avoided the embarrassment of a total whitewash and drew mocking cheers from the crowd in the 10th game when he finally held his serve.

The win gives Dimitrov a 2-0 record and ensures he will play on the weekend in his debut at the season-ending tournament. Roger Federer has also qualified for the semifinals.

In Wednesday's late match, Dominic Thiem defeated Pablo Carreno Busta 6-3, 3-6, 6-4.

Austrian Thiem will next face Goffin on Friday for a last-four spot.

Spaniard Carreno Busta is playing in the place of compatriot Rafael Nadal, who withdrew after his opening loss because of a knee injury. He will next play Dimitrov on Friday.

Goffin beat Nadal in his opening match, calling it the best win of his career.

"This event is really important. It's one of the biggest events of the year. I'm going to focus on the next match, if there is another one. Then we will see," Goffin said.

"I'm not thinking about the Davis Cup for the moment. I know it's just after this event. We will see. I'm just focused on this event."

Associated Press