Rafael Nadal has advanced into the semi-finals of the ATP Finals after defeating defending champion Stefanos Tsitsipas in three sets, 6-4,4-6,6-2.

The 34-year-old Spaniard won the first set while showing consistent form. His service game hit a snag in the second set, allowing the Greek player to force a decider. Nadal then went on to regain the upper hand and proceeded to dominate the deciding set.

"I was playing, I think, a great level of tennis for almost two sets," said Nadal, as quoted by the BBC. The 20-time Grand Slam champion hit 32 winners and made just 13 unforced errors.

"It's always a good feeling when you are playing well and you're playing against the best players of the world. You know you're going to be in a tough fight. That's what happened tonight. I was able to find a way to win. Very happy," Nadal said.

The Spaniard will be facing Russian Daniil Medvedev in the semi-finals at the O2 Arena in London on Saturday.

Medvedev earlier secured his spot in the last four after topping Group Tokyo1970. Earlier in the week, Dominic Thiem was the first player who advanced into the last four after beating both Nadal and Tsitsipas. Thiem's final group stage loss against Andrey Rublev last night did not affect either player's standing. The victory was only a consolation for the Russian who was already eliminated coming into the match.

Novak Djokovic and Alexander Zverev are still vying for the remaining semi-final spot. They will be facing each other on Friday.

All eyes are on Nadal, as The ATP Finals is the one major title the Spaniard has yet to win. He has come close in the past, having lost in the finals on two occasions back in 2010 and 2013.

Rafael Nadal
Rafael Nadal beat defending champion Stefanos Tsitsipas to reach the last four of the ATP Finals AFP / Glyn KIRK