World number one Novak Djokovic has backed the new ATP Cup team event, saying it will provide incentives for leading players to take part.

Djokovic appeared with the ATP and Tennis Australia on Thursday to confirm the event will start in January 2020 as a curtain-raiser to the men’s season.

A revamped Davis Cup tournament will take place in November from 2019.

On Wednesday, Djokovic said he thought two rival events within six weeks would not be “good for the sport”.

The 31-year-old Serb said he feared the situation – which he described as “delicate” – could lead to two “average” events.

“I think in the next two years we’ll have both events happening in a very similar format if not the same, six weeks apart,” the 14-time Grand Slam winner said.

“We have the longest season in all sports. We’re just adding events. We kind of have to try to focus on quality rather than quantity.”

“I think creating one event is an ideal scenario and I think outcome for everyone.”

The ATP Cup will have prize money of £11.35m. It will feature 24 nations in six groups of four and up to 750 ranking points will be available for the winners.

Three Australian cities will host the 2020 event, which will run from 3-12 January and lead into the Australian Open, which starts on 20 January.

Meanwhile, the ITF competition will be an 18-team end-of-season event, which will crown the Davis Cup champions.

The controversial proposals to revamp the Davis Cup were backed by national tennis federations in August, although players were not consulted.

Djokovic, who is the ATP Player Council president, said at the launch of the ATP Cup in London that it was an attractive proposal for the players.

“Having ranking points as an option is obviously an incentive for players,” he said.

“We have a lot of incentives and the biggest one, I’m sure, is playing for your country.

“We have the Davis Cup, which has been the most historical team event, and now we have the ATP Cup, which is definitely going to be right up there in terms of the value from the players’ perspective.”

Earlier in the week, Germany’s world number five Alexander Zverev said he felt none of the top players would play in the Davis Cup.

Analysis

Russell Fuller, BBC tennis correspondent

The ATP Cup will almost certainly be an innovative and enjoyable experience, but the fact remains it will go ahead six weeks after the Davis Cup Finals – even though the head of the ATP said that would be “insane”.

What’s more, both events will be very similar in format.

The ATP prize fund is impressive, albeit US$5m less than the money Kosmos is offering for the revamped Davis Cup.

But the ATP can offer the added pull of up to 750 ranking points for members of the winning team at a time of year which suits the players.

November, in contrast, is a terrible time for a team competition as bodies are tired and injuries rife. Kosmos’ founder Gerard Pique wants the Davis Cup to be staged earlier in the year, but ideally needs the co-operation of the ATP.

Talks continue, but unless common ground is found, there remains a major question mark over the long-term sustainability of the Davis Cup.

Marin Cilic fought back to keep alive his hopes of reaching the semi-finals of the ATP Finals for the first time with victory over John Isner.

The Croat, who has won just two of 11 matches in four appearances at the event, triumphed 6-7 (2-7) 6-3 6-4.

The result puts Novak Djokovic into the semi-finals, leaving Cilic, Isner and Alexander Zverev to fight it out for the group’s other spot on Friday.

It was the first singles match of this year’s event to go to a deciding set.

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Cilic holds his nerve

Cilic has something of a reputation as a bottler – the most recent example coming last week in the quarter-finals of the Paris Masters where he lost to Djokovic despite having won the first set.

And there was a moment here when it looked like he might not hold his nerve.

Having secured rare back-to-back breaks against the tour’s leading server to win the second set and take an early advantage in the third, he then inexplicably dropped serve to give Isner hope.

But he then showed his determination – via some first-class returning and a wonderful drop volley – to secure a third successive break.

With Isner holding on to force him to serve for the match, Cilic showed no sign of wobbling as he brought up three match points and took victory when the American returned a looping second serve wide.

“It was very difficult. The first set was extremely tough. John played a great tie-break and I had to stay focused,” said Cilic, whose only other Finals victory came against Kei Nishikori in 2016.

“I served really well and I am really pleased with the win. I felt that I had that momentum towards the end of the second set. I felt the ball well and got some good points on Isner’s serves.

“He hit a few double-faults on the break points – that helped – but I stayed patient and I managed to break back and play some good tennis towards the end.”

Isner faces Zverev on Friday, while Cilic takes on the already-qualified world number one Djokovic with one other semi-final place at stake.

The other group is back in action on Thursday for their final round-robin matches, with Roger Federer against Kevin Anderson after Dominic Thiem takes on Kei Nishikori. All four in that group have a chance of progressing.

Isner let down by double faults

Isner was playing the day after learning of the death of one of his close friends, Kyle Morgan, and he wore the initials KM on his shoes.

As the leading server on the Tour, it was no surprise that he began the match with a thumping 138mph ace.

He delivered a total of 17 aces against Cilic but was let down by six double faults, including the one that handed the Croat the crucial break in the second set.

The American is making his debut at the tournament after enjoying his best year to date – having reached his maiden Grand Slam semi-final at Wimbledon, won his first Masters 1000 title at Miami and finished the season ranked inside the world’s top 10 for the first time.