San Francisco Frontiers - US Open men's singles: Three talking points

The tennis landscape has shifted slightly since Alcaraz last played in April.

The Spaniard was toppled from the world number one ranking by Sinner that month and is now ranked third behind German Alexander Zverev, who broke through for his first Grand Slam title at the French Open.

Sinner's absence with a knee injury will see Zverev seeded first ahead of Alcaraz in Flushing Meadows, where Serbian great Novak Djokovic will aim to secure a record-breaking 25th Grand Slam title.

Here, AFP Sport looks at three talking points ahead of the tournament, which starts on Sunday at the Billie Jean King National Tennis Center:

- Alcaraz returns -

Alcaraz was riding high earlier this year after his Australian Open victory at the age of 22 made him the youngest man to complete a career Grand Slam.

Flushing Meadows has been fertile ground for the Spaniard, who won the first of his seven major titles at the 2022 US Open to become world number one for the first time and regained the summit with his triumph here last year.

But Alcaraz, now 23, hasn't played since April 16, withdrawing from the Barcelona Open with a right wrist injury and subsequently skipping both the French Open and Wimbledon.

Alcaraz, seeded second, put a toe in the water playing in the US Open mixed doubles tournament with Serena Williams.

He thrilled the Arthur Ashe Stadium Court crowd with flashes of his fearless shot-making but also showed some signs of rust.

Now fans and potential foes will look to see if he can shake that off and show he's fit enough to thrive over best-of-five set matches in the cauldron of New York.

Alcaraz will open his defense against Russian Roman Safiullin and could face American Ben Shelton, who won his second straight Canadian Open title this month, or rising French talent Arthur Fils -- the newly crowned Cincinnati Masters champion -- in the quarter-finals.

Before a title clash with Zverev materializes Alcaraz could find himself up against Djokovic in the semi-finals.

- Djokovic bids to bounce back -

The 39-year-old Serb's latest bid to win a long-awaited 25th major trophy could be buoyed by the absence of Sinner and the uncertainty surrounding Alcaraz.

But since reaching the Australian Open final -- where he fell in four sets to Alcaraz -- Djokovic has been erratic. He lost in the third round at Roland Garros before falling to Sinner in the semi-finals at Wimbledon.

Djokovic struggled physically in his only match since then, a loss to Thiago Tirante in Cincinnati.

Still, no less an authority than Roger Federer says Djokovic -- fueled by skills that haven't deserted him and unshakeable confidence -- still has a chance to break Australian Margaret Court's all-time record for Grand Slam titles.

"I always think that as long as he's in the draw, there's a chance," Federer said this week of Djokovic, a four-time US Open winner. "I think that's also one of the reasons he's still playing, because he actually truly must believe that he can still do it."

- US Grand Slam drought -

With American men's Grand Slam drought stretching into a 23rd year -- since Andy Roddick's 2003 US Open triumph -- Shelton and Tiafoe, along with compatriots Brandon Nakashima and Tommy Paul, will be hoping to make it rain.

Shelton is coming off a successful title defense in Montreal, where he beat Nakashima in the first all-America ATP Masters final in more than two decades.

Nakashima continued his hard-court surge with a quarter-final win over Taylor Fritz in Cincinnati, where he then fell to Tiafoe.

Tiafoe, a two-time US Open semi-finalist, says US men are "knocking on the door" and he's primed to push through it.

"This US Open specifically, I'm ready to see what I can do," Tiafoe said. "I'm excited for it. Take it day by day, take what's ahead of you, take what comes, but yeah, hell yeah, I believe it."

R.Baker--SFF