The US Open gives top-ranked Novak Djokovic a prime opportunity to gain ground on absent Roger Federer and Rafael Nadal in chasing the all-time men’s Grand Slam singles title record.

But a host of rising young stars see a chance for a breakthrough when the New York fortnight begins Monday in a spectator-less Covid-19 quarantine bubble at the US National Tennis Center.

“It’s strange to see empty stands. The circumstances are very unusual,” Djokovic said. “But we have to accept that, we have to deal with it and try to embrace it.”

Top seed Djokovic, who has won five of the past seven Grand Slam crowns, improved to 23-0 this year on Saturday by defeating Canada’s Milos Raonic in the ATP Western & Southern final, also in the New York bubble.

“Going on an unbeaten run so far this year obviously brings even more confidence each match,” Djokovic said. “I’m just trying to enjoy it and embrace the process.”

Despite being bothered by neck stiffness at times, Djokovic showed he remains the man to beat in the Flushing Meadows fortnight as he challenges for tennis history.

“It’s hard to talk about my legacy,” Djokovic said. “I am trying to make the most of my career, trying to use this time when I feel I’m physically, mentally, emotionally, game-wise at the peak and playing some of the best tennis I’ve ever played.

“How long that journey is going to last and what kind of legacy I’m going to leave behind? That’s on somebody else to really judge and evaluate.”

The 33-year-old Serbian star is set to launch his quest for a fourth US Open title and 18th career Grand Slam trophy on Monday night at Arthur Ashe Stadium against Bosnia and Herzegovina’s 107th-ranked Damir Dzumhur.

Swiss legend Federer, who is injured, owns a record 20 men’s Grand Slam titles with Spaniard Nadal, the 2019 US Open winner who skipped New York to focus on next month’s French Open, next on 19.

Djokovic lost a chance to close ground on the elder legends when Wimbledon was cancelled due to the Covid-19 pandemic that shut down tennis from March to August and shuffled the season schedule.

“You can sense that around the site there is a certain tension as well because everyone is being careful,” Djokovic said. “But at the same time, everyone needs to pay attention and follow the protocols and restrictions that are in place.”

The last time a player other than Djokovic, Nadal and Federer won a Grand Slam men’s singles title was when Swiss Stan Wawrinka won the 2016 US Open.

Standing in Djokovic’s path are Austrian second seed Dominic Thiem, third-seeded 2019 US Open runner-up Daniil Medvedev of Russia, Greek fourth seed Stefanos Tsitsipas and German fifth seed Alexander Zverev.

Toss in Italian sixth seed Matteo Berrettini, Canada’s improved Milos Raonic and Spanish eighth seed Roberto Bautista Agut, who battled Djokovic into a third-set tiebreaker Friday at a US Open tuneup, and the field of 128 offers plenty of threats hungry for a first Grand Slam title.

Djokovic’s draw would see him face Tsitsipas or Zverev in a semi-final and a possible final against Thiem, who pushed Djokovic to five sets before falling in this year’s Australian Open final.

Britain’s Andy Murray, who won his first of three Grand Slam titles at the 2012 US Open, lurks in Thiem’s quarter of the draw.