ATP Finals news: Tsitsipas booed after withdrawal as Alcaraz backs up Djokovic complaint

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Brad Gilbert believes Novak Djokovic's 2023 season is the best-ever campaign by a tennis player on the ATP Tour.

Djokovic secured his year-end world No 1 ranking with a win in his opening match of the ATP Finals to mark an incredible season for the Serb.

He won three of the four Grand Slams and only just lost the other in a classic to Carlos Alcaraz as well as three other tournaments including two Masters 1000s.

It's still short of the record 10 titles he won in 2015, but Gilbert believes the 2023 season from Djokovic is the best in the Open Era.

“This is 50th year of @atptour Djoker @DjokerNole his amazing 8th number one finish, 27-1 in slams, missed 4 hardcourt 1000’s hasn’t lost before finals since May, at 36 years young I will put this as best year potentially on men’s tour in 50 years," Gilbert wrote on X.

Drama early in the day as Stefanos Tsitsipas withdraws from his match against Holger Rune after just the third game!

The Greek didn't look comfortable in the early exchanges and decided to call quits after just 14 minutes.

If he withdraws from the tournament then Hubert Hurkacz will take his place to face Novak Djokovic in his final scheduled group game.

Holger Rune has admitted he's trying to learn everything he can from Boris Becker as the Danish tennis sensation looks to take the next step in his career.

Rune is seen as one of the sport's best young stars and a future Grand Slam champion and he's brought Becker into his coaching team to help his progress.

Becker's career will be the ultimate aim for Rune and he's hoping by working together that some of his expertise will rub off on him.

“It's great,” he said. “It's really good. I mean, of course he's right there.

"He's been there many, many times himself, which helps. He can give out from his experience, give that to me on how to handle the things on the court, off the court. Yeah, I mean, we still in the tournament, so let's continue to fight.”

Carlos Alcaraz was once favourite to end the year as the world No 1, but now he's at risk of dropping to third in the world rankings.

His ATP Finals debut ended in defeat to Alexander Zverev while Daniil Medvedev closed the gap to Alcaraz to just 1,055 points.

If Alcaraz ends up losing all his group matches, including the contest with Medvedev in the third rubber, and the Russian goes on to win the ATP Finals then he will move up to No 2 in the rankings.

Novak Djokovic will extend his record for most weeks spent at world No 1 to an unprecedented 400 weeks following the conclusion of the ATP Finals.

Djokovic took the record from Roger Federer two weeks ago when he surpassed the Swiss superstar's tally of 310 weeks before going on to pass WTA legends Serena Williams, Martina Navratilova and Steffi Graf.

He's also set to hold the record for at least 410 weeks before the Australian Open in January.

Carlos Alcaraz has congratulated Novak Djokovic on securing the year-end world No 1 title.

Alcaraz said: "He deserve it, for sure.

"I mean, he has won three Grand Slams and reached the final of the fourth one. He won two or three Masters 1000.

"I mean, he deserve to end the year as No. 1. He has lost just five matches in the year. It's unbelievable. I hear that he said it wasn't the best year of his career."

Greg Rusedski is "sorry" to say that Stefanos Tsitsipas is woefully out of form and is at risk of dropping out of the world's top 10.

Tsitsipas lost to Jannik Sinner in his group opener in the 2023 ATP Finals and must beat Holger Rune today to keep his hopes alive of progressing to the knockout stages.

The Greek star had begun the year in fine form, making it to the final of the Australian Open as well as impressive displays in Paris, Rome and Barcelona.

But he's failed to beat anybody ranked lower than him all year long and Rusedski feels Tsitsipas is on a downward spiral he will struggle to get out of.

He said on Amazon Prime Video: “I’m sorry, he’s not the player he was at the beginning of the season. And if he doesn’t make those improvements at the beginning of 2024, he won’t be in the top 10 to start the year – he’s gonna go out early in Australia.”

Carlos Alcaraz has joined the fight to get ATP Tour bosses to stop changing the balls used at different tournaments after he lost to Alexander Zverev on his ATP Finals debut.

Novak Djokovic admitted last month that he held talks with the sport's governing body as a voice for the players angered by the different balls used on tour.

Alcaraz is the latest to speak out, insisting the ATP have to do something to help stop its best players suffering injuries.

He said: "They should do something, because it is incredible that in three or four tournaments in a row, each one has a different ball.

"I think each tour should have the same ball. In Australia, the same ball. In South America, the same ball. Don’t change it every tournament. I think if I'm not mistaken we have played with 20 or 21 different balls throughout the year. It is crazy.

"There are many players injured by this. If ATP wants to have the best in every tournament, they should change this or they will all be injured.”

Hello and welcome to Express Sport's live blog from the ATP Finals as the players get ready for their second group matches.

Stefanos Tsitsipas and Holger Rune are up first in the Green Group before Novak Djokovic faces Jannik Sinner.

Stay tuned for live updates throughout!