Story highlights

Wozniacki advances to third round

Marta Kostyuk, 15, makes history

Jo-Wilfried Tsonga knocks out Denis Shapovalov in five sets

Rafael Nadal wins in straight sets

CNN  — 

Every year tennis players brace themselves for potentially oppressive weather at the Australian Open – but that doesn’t make it any easier to deal with when the intense heat does arrive.

Wozniacki trailed Jana Fett 5-1 in the third set and stared at two match points on the Croatian’s serve before winning six games in succession to move into the third round 3-6 6-2 7-5 on an eventful Wednesday in Melbourne where temperatures exceeded 30 degrees Celsius.

But that’s nothing compared to Thursday and Friday, when the thermometer is expected to hit 39 degrees.

Djokovic spent as much time in his post-match media conference discussing a players’ meeting last week, one in which he reportedly said that the players should seek more prize money at grand slams and set up a separate players’ union. Those are issues that have surfaced in the past in men’s tennis.

READ: Americans struggle on Day One

Wozniacki must have been boiling over when she heavily fell behind to the 119th-ranked Fett – making her first appearance at a major – in the decider.

Once, though, the newly engaged Dane saved that seventh game she barely put a foot wrong against her now rattled 21-year-old foe, dropping a mere seven points the rest of the way.

‘Kind of lucky’

“At 5-1, 40-15, I felt like I was one foot out of the tournament,” Wozniacki told reporters. “She served a great serve down the T, as well. It was just slightly out. I was kind of lucky.

“Then I felt her tighten up just slightly. I thought to myself, ‘You know what, at this point, make her win it, don’t give it to her.’ When I managed to win it to 5-2, I said, ‘Okay, I’m still alive. She still has four more balls to win in a row or in the game.’

“I was like, ‘Just try and stay aggressive.’ That was that.”

It’s the type of win that could be the spur for Wozniacki, the former world No. 1 who is still chasing an elusive first grand slam title.

Wozniacki said coming from a sporting family – her dad Piotr played professional soccer, mom Anna represented Poland in volleyball and older brother Patrik played professional soccer – helped foster her never-say-die attitude on court.

Sibling rivalry provided extra motivation.

“Growing up, I never wanted to lose, and the worst was to lose to my brother,” she said. “Giving him the opportunity to be ahead, being able to talk s**t to me – sorry for the word – was not pleasurable.

“So I think from that point, you just learn and fight. You don’t give up, even if it’s a board game, tennis, soccer, whatever it is.”

Wozniacki was unquestionably one of the form players heading into 2018, winning the year-end championships in October for the first time and seeing her ranking climb to No. 2 – her highest spot since 2012.

Not having her good pal Serena Williams in the field bodes well for Wozniacki – as well as everyone else.

READ: New mom Serena skips Melbourne

Wozniacki’s next challenge is to get past 30th seed Kiki Bertens in round three.

Another comeback

Although not as dramatic as Wozniacki’s comeback, Jo-Wilfried Tsonga also rallied against Canada’s Denis Shapovalov – one of tennis’ breakout artists in 2017 – in his 3-6 6-3 1-6 7-6 (7-4) 7-5 victory.

The 2008 finalist was almost out of the tournament at 2-5 in the fifth set but claimed five straight games to gain some revenge after Shapovalov ousted him at the US Open.

Grigor Dimitrov seemed to have a comfortable second-round pairing but the third seed was pushed all the way by a flat-hitting US qualifier, Mackenzie McDonald, 4-6 6-2 6-4 0-6 8-6 in an outing that finished 15 minutes shy of midnight on Rod Laver Arena – with another match to come.

Dimitrov landed the biggest title of his career at the men’s year-end championships in November yet in grand slams, hasn’t made a quarterfinal since advancing to the semis in Melbourne 12 months ago. His opponent on Friday, Andrey Rublev, beat the Bulgarian at the US Open so he’ll know about the danger the Russian presents.

READ: Bulgaria rejoices after Dimitrov’s London triumph

Meanwhile, 15-year-old Marta Kostyuk became the youngest player to reach the third round of a grand slam since 1997 when the Ukrainian qualifier defeated Australia’s Olivia Rogowska 6-3 7-5.

At the other end of the age spectrum, the evergeen Ivo Karlovic became the oldest man in 40 years to make the third round at the Australian Open when the 38-year-old edged Yuichi Sugita 7-6 (7-3) 6-7 (3-7) 7-5 4-6 12-10 in four-and-a-half hours.

The huge serving Croatian struck 53 aces and saved 11 of 12 break points a year after outlasting Horacio Zeballos 22-20 in a fifth set in Melbourne.

Ivo Karlovic won a marathon in Melbourne for the second straight year.

Men’s No. 1 Rafael Nadal couldn’t serve out his contest against Leonardo Mayer – a flashy shotmaker who tested the Spaniard at the US Open – in the third set but recovered in the tiebreak with a pair of sizzling passing shots for a 6-3 6-4 7-6 (7-4) win.

Ahead of his tussle with 28th seed Damir Dzumhur on Friday, Nadal called for organizers to use the roof on the three main showcourts that have cover at Melbourne Park.

He said, too, that he wouldn’t be practicing outdoors Thursday.

“If it’s extreme conditions, I hope the organization puts the roof,” he told reporters. “That’s all. I think it’s a health issue, even if I like sometimes (to play in the heat).

“When it’s too much, becomes dangerous for the health. I would not like to see here retirements, conditions that create a bad show for the crowd.

“The crowd is suffering … in the courts that we have the roof, why not put the roof when the conditions are so extreme?”

Rafael Nadal advanced in straight sets over Leonardo Mayer.

Nick Kyrgios like Nadal initially failed to serve out the third set against Viktor Troicki on his favored Hisense Arena but wrapped proceedings up in a tiebreak, 7-5 6-4 7-6 (7-2). That tiebreak featured chair umpire James Keothavong inadvertently being struck in the head by a soft Troicki backhand.

He was okay.

A fan had been earlier ejected for yelling out during play, Kyrgios wasn’t pleased with excess noise stemming from Keothavong’s microphone and at another stage, a helicopter hovered above. It led Kyrgios to proclaim afterward: “The helicopter, that’s when I was thinking like, ‘Of course, it’s at my match.’ It’s just hovering there. Of course it is.”

The combustible 22-year-old raised expectations of a long stay in Melbourne when he won the title in Brisbane and has appeared mostly composed through two rounds, not surrendering a set.

The 17th seed is Tsonga’s next opponent and could tangle with Nadal in the last four.

Winning streak snapped

Julia Goerges topped Wozniacki in the Auckland final this month aided by her hefty serve and entered play Wednesday on a 15-match winning streak but her run was ended by Alize Cornet 6-4 6-3. Cornet has a history of engineering surprises at majors, memorably ousting Williams at Wimbledon in 2014.

Belinda Bencic was unable to follow up her first-round upset of 2017 finalist Venus Williams, Serena’s older sister. The Swiss – who ended last season on a high after back and wrist injuries – was stunned by Thai qualifier Luksika Kumkhum 6-1 6-3.

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Kumkhum’s best performances have come in Melbourne, having upset twice Wimbledon winner Petra Kvitova in 2014.