Nadal seals ATP Finals semis berth

·2-min read

Rafael Nadal kept alive his hopes of winning the year-ending ATP Finals for the first time as he beat Greek defending champion Stefanos Tsitsipas 6-4 4-6 6-2 on Thursday.

The last round-robin match in the London Group was a straight knockout with both men having lost to Austria's Dominic Thiem and beaten Andrey Rublev earlier in the week.

But it was Spaniard who always appeared the likely winner despite a lapse which allowed Tsitsipas to extend the contest into a decider at a near-deserted O2 Arena.

After a flurry of service breaks at the start of the third set, the 34-year-old Nadal pulled away to reach the semi-finals for the first time in five years.

As group runner-up behind Thiem, he will face Daniil Medvedev for a place in the final with the Russian assured of top spot in the Tokyo Group.

"In general this was a very positive match for me," said Nadal, who despite winning 20 Grand Slam titles has only two runners-up places to show for his previous nine appearances at the ATP Finals.

"Excited to be in the semi-finals."

Tsitsipas, who enjoyed his breakthrough moment here last year when, was downbeat about his performance.

"I fought hard in the second set but very disappointed with the third, I was rushing and didn't know what I was trying to do honestly. I should have been a bit more clever," the 21-year-old said.

Russian youngster Rublev signed off from his maiden ATP Finals in impressive fashion by beating Thiem 6-2 7-5.

The aggressive 23-year-old took full advantage of a rather flat performance by Thiem, who had already sealed his place in the final four with two group wins.

Rublev was playing only for pride, although the $US153,000 ($A210,484) bonus for a group stage win provided a sizeable incentive.

"It was not easy for Dommy," said the world No.8, who won a tour-leading five ATP titles this year.

"I think he (was) focused on the semis. I wish him good luck - he deserves to be where he is and he deserves to win the title."

Thiem will shrug off the defeat and now has a day off to prepare for Saturday's semi-final when he will face either world No.1 Novak Djokovic or Alexander Zverev.