NEW YORK (AFP) — Novak Djokovic, fired up by his emotional Olympic Games triumph, targets new Grand Slam records at the US Open as title rival Jannik Sinner arrives in New York dogged by questions over two positive drugs tests.

Defending champion Djokovic can become the oldest Open era champion at the tournament if he secures a fifth title, a record he would share with Jimmy Connors, Pete Sampras and Roger Federer.

The 37-year-old would also move to 25 Grand Slam triumphs, taking him clear of the 24 he currently shares with Margaret Court.

The final major of the year comes at a critical time for Djokovic.

This year, he was succeeded as Australian Open champion by Sinner who also relieved him of his world No. 1 ranking.

Carlos Alcaraz took his French Open title with the Spanish crowd-pleaser then sweeping Djokovic off court in a one-sided Wimbledon final.

However, Djokovic returned to the clay courts of Roland Garros to stun Alcaraz in the Olympic final.

His tearful victory in Paris allowed him to become only the fifth player to complete a career Golden Slam of all four majors and Olympic gold.

The victory also silenced the increasing number of doubters who had written off the Serb as a spent force in a new era where Sinner, 23, and 21-year-old Alcaraz are steadily moving centerstage.

Djokovic, who underwent surgery on his right knee in June, described his Olympic victory as his “biggest sporting success.”

It was also the 99th title of his professional career.

“At the age of 37 and facing a 21-year-old who is probably the best player in the world right now, winning Roland Garros and Wimbledon back-to-back, I can say that this is probably the biggest sporting success I have ever had,” Djokovic said.

Sinner arrives at the final Slam of the season having captured the Cincinnati Masters title.

But that triumph was quickly overshadowed when it emerged he had been cleared of any wrongdoing after twice testing positive for a banned substance earlier in the season.

Sinner tested positive for clostebol, an anabolic agent prohibited at all times by the World Anti-Doping Agency.

But he escaped a lengthy ban after officials accepted his explanation that the substance had entered his system as a result of contamination from a support team member.

“I will now put this challenging and deeply unfortunate period behind me,” Sinner said.