NEW YORK (REUTERS) - Second seed Rafael Nadal faced a surprise test in his first US Open appearance since winning the 2019 title, as he overcame 21-year-old Australian wild card Rinky Hijikata 4-6, 6-2, 6-3, 6-3 on Tuesday (Aug 30) in the opening round.

Playing in only his second match after pulling out of Wimbledon with an abdominal injury, the Spaniard had speculated whether he was ready to take on New York and seemed to confirm those fears as he struggled on the return in the first set.

Hijikata incredibly broke the 22-time Grand Slam winner with a crisp overhead shot in the seventh game of his Slam debut, bringing the crowd to a roar.

"I started not that bad the first couple of games, but then I had some opportunities that I was not able to make," Nadal, 36, said after the match. "I didn't play a good game with my serve. Then he had the break. Then I was a little bit nervous."

The win extends Nadal's unbeaten streak in Grand Slam competition this year, after he won the Australian Open and Roland Garros, with the world No. 1 ranking on the line in New York in a depleted men's draw.

"You need to be humble enough to go through this process and accept that you need to fight and you need to accept that you going to suffer," he said. "That's what I did today."

In women's play, Danielle Collins showed no signs of rust, battling past twice US Open champion Naomi Osaka 7-6 (7-5), 6-3 into the second round.

The exit of Osaka, the tournament winner in 2018 and 2020, followed reigning champion Emma Raducanu's departure hours earlier as Flushing Meadows bid a first-round farewell to its past two champions.

Both players arrived in New York on the comeback trail after injury-interrupted campaigns. Collins missed the entire North American hard-court swing, withdrawing from San Jose, Toronto and Cincinnati, because of a neck injury.

"I lost to Naomi three times before, so going into the match I had a lot of information on what I kind of needed to do better, areas I could improve," said Collins. "I felt happy just to be out here playing.

"I think when you face as many challenges as I've faced with some of the things I've been dealing with, you're kind of more grateful to kind of be out here."

Osaka, who lost to Amanda Anisimova in the first round of the French Open, sat out the entire grass-court season before falling in the opening round of the Toronto and Cincinnati events.

The 24-year-old said she was happy to have played through the match without her back flaring up and only began serving on Sunday.

"Honestly, I just wanted to play without my back being in pain because it's kind of been bad for the entire hard court season since Toronto," she told reporters. "I didn't serve until two days ago so I was really happy with how it went.

"Overall I wouldn't say that I played well ... I felt like I was on my back foot a lot," she added. "Everyone deals with injuries. For me, it's been more prominent this year, but it's something that I can learn (from).

"I learnt a lot more about my body, I learnt what's weak, what I can do to prevent it. I would say the sport is definitely very physical, but it's kind of my job to stay on top of it."

Despite the layoffs, Collins and Osaka delivered high-energy tennis that was welcomed by fans who stuck around for the final match that got under way late on Tuesday evening and finished early on Wednesday morning.

Earlier, 2000 and 2001 winner Venus Williams made a quiet exit after losing 6-1, 7-6 (7-5) to Belgian Alison van Uytvanck in front of a half-empty Arthur Ashe Stadium.

The subdued scene was in stark contrast to what unfolded on Monday when a raucous star-studded crowd filled the world's biggest tennis venue to cheer on her younger sibling Serena to a 6-3, 6-3 win over Danka Kovinic in her Flushing Meadows opener and then celebrated the 23-time Grand Slam winner's career.

In contrast Venus, 42, exited to polite applause and no fanfare. "I definitely watched it," she said when asked about her sister's elaborate farewell ceremony.

"I wanted to be there, but I had obviously an early start today.

"It's never easy the first round. "Definitely was an exciting evening. Obviously my hope is that there is more ahead for her at this tournament."

Doubles focus

While Serena has been coy about her future, Venus has been tight-lipped, with every indication she plans to carry on.

Asked directly after her loss to van Uytvanck if she too might be preparing to evolve away from tennis, she was blunt. "Right now I'm just focused on the doubles," said the senior Williams.

She will compete in the doubles with Serena at the year's final major for the first time since 2014.

"It was Serena's idea. She's the boss, so do whatever she tells me to do," said Venus.