NEW YORK, Aug 26 (Reuters) - Novak Djokovic heads to the U.S. Open chasing a record 25th Grand Slam title, but his latest bid for history carries renewed questions over whether his 39-year-old body can withstand perhaps tennis's most punishing fortnight.
The four-times U.S. Open champion has reached a men's record 10 finals in New York. Another title at Flushing Meadows would take the Serbian beyond Margaret Court's 24 major singles crowns and give him sole possession of the all-time record.
He reached the Australian Open final this year after beating Jannik Sinner in a five-set semi-final and also reached the Wimbledon semi-finals, but his Cincinnati Open defeat this month offered a reminder of the physical margin he must manage.
Playing his first match since Wimbledon, Djokovic swept through the opening set against Argentina's Thiago Agustin Tirante before the stifling humidity affected him.
The Serbian dropped to his knees during an 18-minute service game in the second set and received treatment before losing 2-6 6-4 6-4.
"It's simply a health issue I have. It's been troubling me for the past few years," Djokovic said after the match. "I have a lot of problems, especially when there's high humidity and heat."
The episode adds weight to the familiar challenges of the last Grand Slam of the season: late-summer heat, heavy humidity, hard courts and the seven gruelling rounds of hard-fought matches required to win the title.
Sinner's withdrawal with a right-knee injury has removed one of his most difficult opponents, yet defending champion Carlos Alcaraz remains the leading potential threat despite arriving after time out with a wrist injury.
The 23-year-old Spaniard beat Djokovic in last year's U.S. Open semi-finals and in January's Australian Open final, while French Open champion Alexander Zverev, Americans Ben Shelton and Taylor Fritz and a younger generation increasingly unburdened by Djokovic's aura could make for a dangerous field.
Djokovic's greatest asset is his experience. Few players can match his ability to withstand pressure while adapting through a five-set contest. Yet he has less room for error than during his most dominant years.
A favourable early draw, efficient service games and short opening-week matches could prove vital if he is to save enough energy for the final rounds, especially as his quest for history may depend on his body keeping pace with his ambition.
(Reporting by Angelica Medina in Mexico CityEditing by Toby Davis)
