David Goffin caused one of the upsets of the year when he defeated Roger Federer in the semi-finals of the ATP Tour Finals at the O2 Arena in London on Saturday night.

Federer came into the tie as red-hot favourite having thrashed Goffin on the same surface only three weeks earlier. To say that Goffin struggled against the Swiss maestro would be quite the understatement, with the Belgium having never beaten Federer in 19 fruitless attempts.

Federer looked well on course to cruise into yet another final after winning the first set before Goffin burst into life in the second, forcing his way back into the tie as he went on to complete one of the biggest wins of his career 2-6, 6-3, 6-4.

After the game, Goffin revealed how managed to turn the tables so dramatically and recover from a dreadful first set.

“When I started to play against him, I was a little bit nervous,” said the Belgian.

“I started to be just solid. But against him it’s not enough to be just solid, because it’s perfect, the perfect pace for him, he can do whatever he wants.

“Then I wanted to change something because I was nervous.

“I started to feel the ball better at the end of the first set, so I wanted to be more aggressive.

“As soon as I had the chance to go for the shot from the return and from the serve also was the key to go for the shot.

“It paid off. I started to serve well.

“My forehand was going much better. I was really aggressive. I came to the net.”

Federer will be bitterly disappointed with himself after converting just two of the 11 break points he created, with Goffin proving far the more clinical, breaking twice from just three opportunities.

Thankfully, from Goffin’s point of view, he was able to overcome his nerves when serving out the match after they wreaked havoc over his attempt to do the same against Rafael Nadal earlier in the week.

“It was good there was a screen on the changeover,” Goffin added.

“I was more relaxed so I didn’t think about the first point or the game I have to play.”

Goffin became the first man to beat both Nadal and Federer in 2017 and will be desperate to go one step closer and claim the prestigious season-ending prize.