Nick Kyrgios has overcome a wardrobe malfunction and serving arm soreness to safely progress to the Australian Open third round in Melbourne.

The colourful youngster swept aside Uruguayan claycourt specialist Pablo Cuevas 6-4 7-5 7-6 (7-2) in one hour and 58 minutes on Wednesday night despite engaging in a running battle with his own entourage over a problematic pair of shorts.

The pockets were seemingly not deep enough to contain balls, leaving Kyrgios needing to fetch one from a ballboy between first and second serves.

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He fumed at his camp for taking a set and a half to find a replacement pair before finally taking a toilet break almost an hour into the contest to change pants.

Cuevas protested at chair umpire Carlos Ramos, but to no avail as Kyrgios returned a new player to dominate the rest of the match and set up a third-round clash with Czech sixth seed Tomas Berdych.

Commentators called the brief stoppage a game changer, with Roger Rasheed saying “that’s a mistake by the central umpire” and former world No.1 Jim Courier even casually accusing Kyrgios of “tanking the last service game” before changing shorts.

Kyrgios had a few choice words to say to himself and his camp. Photo: AAP

In reality, Cuevas was never really in the contest.

His outfit woes aside, Kyrgios was in complete control.

Fined $US3000 ($A4340) earlier on Wednesday for dropping the F-bomb in his first-round win over Pablo Carreno Busta, Kyrgios stayed out of strife in taking down the South American in straight sets.

He bit his lip and showed true grit to save break point after copping a late overrule from Ramos in the opening set.

One break of his own, coming in the third game, was enough for Kyrgios to secure the set, clinching it with a lovely wide-angled second-serve ace.

He forced another early break in the second set, letting out a huge roar – a mix of frustration and delight – after taking command of the match.

Kyrgios peeled off three straight games after his service lapse to nab the second set and gained another break to go 2-1 up in the third.

The 29th seed required a medical timeout to have his right arm massaged and had to stave off successive set points after dropping serve for the second time and then finding himself down 4-5 and 15-40.

But after regrouping, Kyrgios closed out the match in a tiebreaker with a ferocious backhand crosscourt winner.

He finished with 19 aces, 50 winners and just 27 unforced errors.

Kyrgios and Berdych have never previously met, but the world No.6 – a semi-finalist at Melbourne Park for the past two years – shapes as the Australian’s biggest test yet.

Gavrilova knocks out sixth seed

Daria Gavrilova continues to fly the flag for her newly adopted nation at the Australian Open, stunning sixth seed Petra Kvitova to march on to the third round.

Gavrilova upset the two-time Wimbledon winner 6-4 6-4 in 89 minutes to book a date with Kristina Mladenovic in the last 32 at Melbourne Park.

The 21-year-old, who was born in Moscow but confirmed her switch of allegiances to Australia late last year, produced a sparkling display on Margaret Court Arena.

The win ranks as one of Gavrilova’s best, perhaps behind only a defeat of then-world No.2 Maria Sharapova in Miami last year.

It was all smiles for Daria Gavrilova at Margaret Court Arena. Photo: Getty

“It was unreal,” Gavrilova said.

“I was so nervous at the end. I’m just really proud.”

Gavrilova and Kvitova traded heavy groundstrokes in a high-quality meeting.

The effervescent Gavrilova was broken twice in the first set, lashing out each time.

She threw her racquet after a string of double faults to trail 2-3, and kicked a ball in disgust.

But each time she responded to break straight back, her fist-pumps becoming more frequent as she grew in confidence.

In faultless end to the set, Gavrilova won three games without dropping a point to carry all the momentum into the second set.

A key moment then arrived at 2-3, with Kvitova twice double faulting and making two errors to give away her serve.

Gavrilova served for the match at 5-3 but wobbled, losing the next three points to put the match back on serve.

In front of a vocal crowd, Gavrilova calmed her nerves and broke straight back to reach the third round of a major for the first time.

While Gavrilova’s effort would have troubled Kvitova at her very best, the towering Czech was not near it.

The world No.6 came to Melbourne Park with a lack of match practice, having pulled out of tournaments in Sydney and Shenzen with a gastro-intestinal problem.

The Czech joins world No.2 Simona Halep and No.8 Venus Williams as high-profile early departures from the tournament.

-AAP