Nadal straight into the groove at ATP Finals, win for Thiem

London is bidding farewell to the ATP Finals after hosting it since 2009 but Rafa Nadal has unfinished business alongside the River Thames and his opening win over Andrey Rublev on Sunday suggests he is ready to land the one big title to elude him.

The 34-year-old Mallorcan has struggled at the ATP's year-ender with two runner-up finishes in London his best showings.

Often he has arrived physically spent after gruelling years, but he looked full of beans in a 6-3 6-4 victory that put him top of the London Group, ahead of Austrian Dominic Thiem who got his campaign off to a fine start with a 7-6(5) 4-6 6-3 victory over Stefanos Tsitsipas who he lost to in the 2019 final.

Nadal will face Thiem on Tuesday.

After winning the French Open last month for a 13th time, Nadal sounded unsure whether he would appear in London.

The fact he is here, with London in Covid-19 lockdown and the O2 Arena without any fans, shows that he regards it as a great opportunity to finally win the title.

Often a slow starter indoors, Nadal was straight into the groove against Rublev, whose five titles this year is more than any other player on the ATP Tour.

Rublev was a little unlucky to drop serve at 2-3 in the first set, his forehand flicking the net and landing out.

But after that it was a foregone conclusion with Nadal rock-solid on serve and clinical from the baseline.

"I think it's a positive start," Nadal said. "Always here the first match is tricky. You are playing the best of the best. Now I have a super tough match against Dominic."

Twelve months ago Tsitsipas beat Thiem in a three-set humdinger in front of a 18,000 fans.

This time, while the quality of their tennis was high, the atmosphere felt depressingly flat in the cavernous arena, hardly the farewell party the ATP envisaged for the 50th edition of their blue-riband event before it uproots to Turin.

There was nothing between them in the first set but Tsitsipas, who saved the only break points on offer, looked set to take the opener when he led 4-1 in the tiebreak, only for Thiem to hit back.

On set point down Tsitsipas had the court at his mercy with an easy put-away but Thiem guessed right to get back into the point with a lob and then forced an error.

Tsitsipas quickly re-grouped to break early in the second set on his way to levelling the match.

But Thiem, who broke into the Grand Slam winners' club at the U.S. Open, is made of tough stuff these days and raised his game at the start of the decider to grab the decisive break.

The world number three said it was hard to play in front of empty seats though.

"If you have a huge win like today and you get the atmosphere from 17,000 people, it brings so much positive energy, and all of this is missing," Thiem said.

"You have all the time to push yourself, give yourself energy."

Greek Tsitsipas succinctly summed up the difference between this match and last year's clash on the same court.

"Main differences? People in the stands," he said.