San Francisco Frontiers - Five talking points ahead of the US Open tennis championships

Out to stop him will be Italian Jannik Sinner, the Australian Open winner who seized Djokovic's world number one ranking this year, and Spain's third-ranked Carlos Alcaraz -- who succeeded Djokovic as French Open champion then dominated Djokovic in the Wimbledon final.

The women's draw, headlined by world number one Iga Swiatek, looks wide open. With defending champion Coco Gauff struggling to find consistency, the array of contenders includes Australian Open champion Aryna Sabalenka, Wimbledon winner Barbora Krejcikova and Olympic gold medallist Zheng Qinwen.

AFP Sport looks at five talking points before the US Open begins in Monday:

Can Djokovic keep Slam streak alive?

It's been seven years since Novak Djokovic finished a season without a single Grand Slam title, but the 37-year-old Serb isn't ready to pass the torch to a new generation just yet.

After the euphoria of his Paris Olympics triumph he is ready to get down to business in his first hard court tournament since a third-round exit at Indian Wells in March.

"Grand Slams and representing my country -- that's what actually motivates me the most," Djokovic said.

Alcaraz brings a 14-match major winning streak to Flushing Meadows, where the 21-year-old has never been knocked out before the quarter-finals in three appearances. He won his maiden Grand Slam title here in 2022 and reached the semis last year.

Trying to regroup after a devastating Olympic defeat, Alcaraz cut short a practice session when he twisted an ankle on Saturday. But the third seed insisted he'd be "100 percent" for his Tuesday opener against Australian qualifier Li Tu.

Sinner seeks to leave drugs controversy behind

Jannik Sinner escaped a lengthy doping ban as authorities cleared him of wrongdoing despite two positive drugs tests back in March, but it remains to be seen if he can escape questions as to whether he received preferential treatment because of his world number one ranking.

Sinner was still celebrating his Cincinnati Masters triumph when the International Tennis Integrity Agency on Tuesday announced the results of the investigation into his positive tests -- the first that most in the sport had heard of it.

Sinner has sacked the physio therapist and trainer whose use of a wound-treating spray resulted in his positive test for banned clostebol.

"I was struggling a lot in the last months. Now I was waiting for the result, and now I just need some clean air," Sinner said.

But his colleagues on the ATP Tour have questioned the process and, in particular, what they see as a lack of transparency.

"I guess in this ruling they found that it's different and there's no ban, and I trust that he wasn't at fault or purposely doing anything," American Taylor Fritz said.

Top-ranked Swiatek travelling light

Poland's Iga Swiatek is taking a softly-softly approach to the final Grand Slam of the year.

Last year Swiatek arrived in New York feeling the pressure to retain the title and maintain her number one world ranking.

"I felt like I have a lot of baggage on my shoulders," said Swiatek, who earned a fifth Grand Slam title at Roland Garros this year.

"This year I'm just trying to focus on what should I do tennis-wise to play the best game possible," added Swiatek, who opens on Tuesday against Kamilla Rakhimova.

"My expectations are not so high compared to last year. I'm going to try to focus on getting everything step by step and not put too much baggage on my shoulders."

Not-so-Late show

Matches finishing in the wee hours are a staple at the US Open, the Grand Slam held in the City That Never Sleeps.

Rollicking night sessions under the lights of Arthur Ashe Stadium will still feature, but under a new policy the tournament referee will be able to move the last match on a show court if it hasn't started by 11:15 p.m.

Increasingly late finishes sparked the ire of players at the Australian Open and French Open this year. But some players say late matches are part of the unique fabric of the US Open.

"I think New Yorkers like to stay up late," Danish veteran Caroline Wozniacki said.

Let's review

The US Open, which last year became the first Grand Slam to implement video review, will expand the technology from five to eight courts.

The system is designed to avoid the kind of controversy that erupted at Cincinnati this month when Britain's Jack Draper defeated Felix Auger-Aliassime in the quarter-finals on a dubious line call that the chair umpire wasn't in position to overrule.

Once a challenge is made, multiple camera angles are sent to the chair umpire's tablet and a decision is made based on the footage.

US Open tournament referee Jake Garner said the expanded review system "covers about 75 percent of our singles matches."

M.Hill--SFF