Nick Kyrgios’ Australian Open comeback fell at the first hurdle and now his Davis Cup return after a five-year absence is in doubt after Australian captain Lleyton Hewitt conceded the 29-year-old was “not 100 per cent” sure about his body.

After losing his opening round match to Britain’s Jacob Fearnley at Melbourne Park on Monday night in three sets, still restricted by an abdominal strain he suffered on the eve of the tournament and testing the wrist he had surgically repaired, Kyrgios conceded he might never play singles at the January grand slam again.

While he stopped short of retiring on the spot, confirming he’d play doubles with good mate Thanasi Kokkinakis and hoping he is “still be able to do some cool things this year at some stage”, the Davis Cup tie with Sweden could come too soon.

Kyrgios was a shock inclusion in a four-man playing squad named by Hewitt for the tie, which begins on January 31 in Stockholm, having not played a Davis Cup tie under Hewitt since 2019.

Upon his selection, Kyrgios quickly dismissed any suggestion of a poor relationship with Hewitt, and even Australia’s top-ranked player, Alex de Minaur, a Davis Cup regular, said he was “excited” to have a new teammate.

But during Monday night’s defeat, Hewitt lamented that Kyrgios didn’t seem up to the rigours of top-flight tennis given the state of his body.

“Mentally and physically I think deep down he is not 100 per cent sure,” Hewitt said.

“He wasn’t sure how the wrist would hold up, especially in matches. You can play a lot of points out of the hand from the baseline and hit a lot of balls on the practice court.

“It is completely different when you are out there on the match court, and also this is just the first match.

“How he pulls up, if he is able to get through a five-set match, we all know how hard that is.”

Kyrgios also lost his return to competitive tennis, at the Brisbane International, but played two doubles matches with 24-time grand slam champ Novak Djokovic.

The 2022 Wimbledon runner-up, who still plans to play doubles with buddy Kokkinakis, said he didn’t expect to make it back to grand slam level.

“All the niggles, I guess, my body compensating with the wrist is tough,” he said.

“I don’t have any regrets. Everything’s been a learning curve for me.

“I continue to try and have fun and just be real and enjoy the ride.

“But I think it would be selfish for me to say that ‘I want more, I want more’. I’ve had a lot of success, more than most athletes would have.”