MELBOURNE  -   Push Simona Halep to the brink, and she summons her best. The Australian Open’s top-seeded woman got all she could handle from 20-year-old American Sofia Kenin in the second round before taking the last four games to emerge with a 6-3, 6-7 (5), 6-4 victory that took 2½ hours Thursday.

“Well, I have no idea how I won this tonight,” said Halep, the reigning French Open champion. “It’s so tough to explain what happened on court.”

A year ago at Melbourne Park, Halep was a point from being eliminated in two matches but came back each time en route to reaching the final. In the first round this year, she was down a set and a break before turning things around. And this time, against a hard-hitting Kenin, Halep trailed 4-2 in the third set and managed to not cede another game.

And that was despite getting what she described as “a little bit injured” in the second set, something that seemed clear from the way she wasn’t always able to run with her usual verve. “Hopefully,” said Halep, whose No. 1 ranking is up for grabs during the Australian Open, “next round I play better.”

That third-round matchup will be quite intriguing, because it’ll be against seven-time Grand Slam champion and former No. 1 Venus Williams. And the winner of that could face Williams’ younger sister, 23-time major champ Serena, in the fourth round.

Venus won a three-setter that finished a little before Halep’s did -- and in much more emphatic fashion. Pushed to that deciding set by getting broken to end the second, Venus ran away with the win down the stretch, defeating Alize Cornet 6-3, 4-6, 6-0.

So what was the difference in the lopsided third set? “She was just putting more intensity than me. She was hitting harder, deeper,” Cornet said. “I had a little less energy than in the second set and she took advantage of it and really raised her level.”  The 38-year-old Venus, unseeded at a major for the first time in five years, was the runner-up in Australia to Serena in 2003 and 2017.

Other winners in the women’s draw included reigning U.S. Open champion Naomi Osaka, past U.S. Open runners-up Karolina Pliskova and Madison Keys, No. 27-seeded Camila Giorgi and No. 28 Hsieh Su-Wei.

Djokovic thrashes Tsonga, Zverev survives 5-set battle

Eleven years after beating Jo-Wilfried Tsonga for the 2008 Australian Open, top seed Novak Djokovic bested the Frenchman again at Melbourne Park to reach the third round early on Friday. The world number one Serb claimed a clinical 6-3 7-5 6-4 win over wildcard entry Tsonga in the late match at Rod Laver Arena. While Djokovic is seeking a third successive Grand Slam title, Tsonga has been on a different trajectory, with his ranking slipping to 177 after his 2018 season was cut short by a knee injury in April.

The gap between the players’ standing was on full show as Djokovic cruised to victory in two hours and four minutes, setting up a mouthwatering intergenerational clash with Canadian teenager Denis Shapovalov.

Germany’s Alexander Zverev wasted a flurry of opportunities before securing a 7-6(5) 6-4 5-7 6-7(6) 6-1 win over unseeded Frenchman Jeremy Chardy to book a place in the third round on Thursday. Chardy ran out of steam in the final set as his errors mounted and Zverev cantered to victory in three hours and 46 minutes. He next plays local wildcard Alex Bolt, who stunned 29th-seeded Frenchman Gilles Simon 2-6 6-4 4-6 7-6(8) 6-4.

Stan Wawrinka was up a set and was just two points away from taking the second against Milos Raonic. Couldn’t do it. About an hour later, 2014 champion Wawrinka was a single point from grabbing the third set. Denied again. And another hour after that, Wawrinka was two points from seizing the fourth to force a fifth. Nope, not on this afternoon.

Wawrinka kept coming oh-so-close, and Raonic kept hanging in there and toughing out the most important moments along the way to a 6-7 (4), 7-6 (6), 7-6 (11), 7-6 (5) victory that put the 16th-seeded Canadian into the third round.  In other men’s action on Day 4, 2014 US Open runner-up Kei Nishikori withstood 59 aces from 39-year-old Ivo Karlovic en route to a 6-3, 7-6 (6), 5-7, 5-7, 7-6 (7) victory, but No. 7 Dominic Thiem retired from his match in the third set after dropping the first two, and 2018 Australian Open semifinalist Hyeon Chung lost to Pierre-Hugues Herbert 6-2, 1-6, 6-2, 6-4.