Australia’s Thanasi Kokkinakis suffered a flare-up of his shoulder injury but has defied pain to notch a gallant victory in his first singles match in almost a year.

Kokkinakis, who had radical surgery last February to try to fix a long-standing pectoral problem, downed American Sebastian Korda at the Adelaide International on Monday night.

After fellow Australian Alexei Popyrin departed the tournament with another first-round loss – his second such exit in a week – a hobbled Kokkinakis triumphed 3-6 6-3 7-6 (7-3).

Kokkinakis, in his first singles outing since January 15 last year, played through pain to courageously finish his comeback match.

But he frequently received medical treatment, casting doubt on any appearance at the Australian Open starting on Sunday.

The 29-year-old has a protected ranking to enter the singles at Melbourne Park, where he’s also scheduled to play doubles with Nick Kyrgios.

But Kokkinakis said he was determined to return to action on Wednesday in Adelaide.

“We are so far away from the courts tomorrow. I am going to be put on ice, try and take the strongest painkillers, and see as many physios as I can,” he said.

Last February, Kokkinakis had a dead person’s Achilles tendon attached to his right pectoral muscle and shoulder.

The first tennis player to have such surgery, he made his competitive return in doubles with Kyrgios last week at the Brisbane International.

But the injury flared during his singles comeback after a raucous reception walking on to centre court in his home town.

Kokkinakis sent down first serves consistently around 195km/h in the opening set.

World No.51 Korda took the set before Kokkinakis raced to a 3-0 advantage in the second when his injury resurfaced.

Grimacing and feeling his shoulder, he called a medical timeout.

At 4-1, the 29-year-old again received massage treatment at the change of ends yet defied his pain to break Korda’s serve in the next game.

Adopting daringly aggressive tactics in a bid to shorten rallies, Kokkinakis ultimately won the set 6-3 despite his service speed dropping about 20km/h and consulting with his team about whether to continue.

Korda appeared prepared for Kokkinakis to retire when the Australian left the court – but he returned for the third set, when almost every rally ended with the Australian clutching his shoulder.

The set went to a tiebreak, in which Kokkinakis somehow produced one 196km/h serve as he closed out a remarkable victory.

“I know what tomorrow is looking like for me – and I don’t love it,” he said afterwards.

“Fingers crossed, the anti-inflammatories work some wonders.”

Asked if he would have retired if it wasn’t his home tournament, Kokkinakis said: “I probably wouldn’t have played to start to with.”

“I had conversations with my team: I was like: ‘At what cost am I playing? Even if I get through this match, so what?’

“I had the surgery so I could back-up matches and go through a tournament. But I’ll never really find out until I go through a long match and see where I’m at after.”

Kokkinakis said it was a different pain to the pectoral problems that had long plagued him.

“I had a pec surgery, that was more muscle; this one is in my shoulder,” he said.

“I have had a shoulder surgery as well, but that was probably caused from the surgery I had to the pec.

“So there’s a lot of niggles and a lot of things going on.”

Earlier, Popyrin remained bullish despite consecutive first-round exits to start his new tennis year.

Red-hot American Reilly Opelka outgunned the Australian, pounding 22 aces in his 6-3 7-6 (8-6) triumph.

Popyrin’s straight-sets loss followed his defeat last week in the first round at the Brisbane International to French qualifier Quentin Halys. But the world No.49 was adamant the signs aren’t all doom and gloom ahead of the Australian Open.

“Everything that we’ve been doing is good and it’s working,” Popyrin said.

“It might not be showing in the first two weeks of the year but I’m looking forward to the AO. I think I can do some stuff there.

“Physically, mentally, I’m feeling the best I have felt in a long time … it’s only a matter of time before results will come.”

-AAP