British rising star Jack Draper tested Spain's Rafael Nadal before physical issues cost him in a four-set loss in the Australian Open first round.

Draper, 21, levelled at one-set each, leading to 22-time major champion Nadal, 36, having a frank discussion with his team before the third set.

Top seed Nadal led 4-1 but was still unconvincing as Draper broke back before the Briton lost serve at 5-4.

Draper struggled to move in the fourth as Nadal secured a 7-5 2-6 6-4 6-1 win.

Britain's Kyle Edmund was also knocked out on the opening day at Melbourne Park with a 6-4 6-0 6-2 defeat by Italian 15th seed Jannik Sinner.

Edmund, 28, reached the semi-finals in 2018 but is trying to rebuild his career after a knee injury which needed three operations before he returned to the tour last year.

Playing using a protected ranking, it was another tough draw at a Grand Slam for Edmund after he faced eventual runner-up Casper Ruud at last year's US Open.

Cameron Norrie, seeded 11th, is aiming to avoid a clean sweep of defeats for the Britons in the men's singles on Monday when he plays French wildcard Luca van Assche.

In the women's singles, Emma Raducanu made a positive return to court after her injury scare in the build-up to the Grand Slam.

The British number one moved into the second round with a straight-set win over Germany's Tamara Korpatsch and could be joined there by Harriet Dart, who plays Swiss 32nd seed Jil Teichmann.

Encouraging for Draper but work still to do

For a good while on Rod Laver Arena it looked as though Draper could cause a stunning upset against a player he described as one of his "heroes".

His ball-striking caused problems for Nadal throughout, but the physical issues which have dogged the left-hander's burgeoning career returned.

Draper collapsed at the Miami Open in 2021 with a heat-related illness and was also forced to retire from his US Open third-round match last year when in a decent position against Russian 28th seed Karen Khachanov.

This time, he struggled with what appeared to be cramp and needed treatment from the physio in the third set.

By the latter stages of the fourth, Draper - who has risen to 38th in the world after being outside the top 250 last year - was unable to push off on serve.

Developing his body for the rigours of the ATP Tour was the priority in a gruelling pre-season regime, hiring former Olympic sprinter and bobsleigher Dejan Vojnovic as a fitness coach.

This was another reminder the team have more work to do on improving the youngster's physicality.

But performances like this reiterate he appears to have an exciting future ahead as he embarks on what is still only his first full season on the ATP Tour.

"I played one of the toughest possible opponents in the first round," said Nadal.

"He is young, he has power and has a great future ahead. We will see him play for many years ahead."

Nadal proves to be vulnerable

Defending champion Nadal is the top seed in the absence of injured world number one Carlos Alcaraz but, after six defeats in his previous seven matches, admitted he was vulnerable to losing against Draper.

So it proved. Nadal was far from his best, seeming to lack speed and making a catalogue of uncharacteristic errors.

Amid a backdrop of vocal support for the Spaniard, Draper started confidently and matched his illustrious opponent for the bulk of the opening set.

Shot selection between the pair proved key in the pivotal stages. An audibly annoyed Draper rued hitting a poor forehand into the net at 5-5 deuce on Nadal's serve and was punished for two weak drop shots in the 12th game.

But Draper retained his level in the second set and threatened to bagel the struggling Spaniard, who produced 24 unforced errors.

Nadal's frustrations showed when he was involved in an animated conversation with coach Carlos Moya and whatever was said seemed to encourage the former world number one to play more aggressively.

However, he was chiefly helped into a 4-1 lead by Draper throwing in a pair of double faults in the fifth game and the Briton's weakening condition.

In the end, Nadal cantered to the fourth set and secured a meeting with American world number 65 Mackenzie McDonald in the second round.