MELBOURNE, Jan. 22 (Xinhua) -- Wang Xinyu ensured China will be represented in the Australian Open third round after a fighting win over former French Open champion Jelena Ostapenko on Thursday, while second seeds Jannik Sinner and Iga Swiatek rounded into form.

On a cool and windy day in Melbourne, Wang was down a set and a break before digging deep to prevail 4-6, 6-4, 6-4 in two hours and 20 minutes.

World No.46 Wang is China's highest-ranked player in Melbourne after Zheng Qinwen, a former world No.4, withdrew ahead of the tournament.

Wang now faces 13th seed Linda Noskova of the Czech Republic, who defeated Australian wildcard Taylah Preston.

Elsewhere, world No.168 Wu Yibing's indefatigable run ended after his comeback effort fell agonizingly short against American Eliot Spizzirri, who prevailed 6-2, 6-4, 6-7 (4), 4-6, 6-3 in three hours and 43 minutes.

A weary Wu will leave encouraged by his form in Melbourne after winning four matches, including three in qualifying.

Spizzirri will next face defending champion Sinner, who fired 18 aces in his commanding 6-1, 6-4, 6-2 victory over Australian wildcard James Duckworth.

Shang Juncheng faded after a bright start against Botic van de Zandschulp, who powered to a 7-6 (6), 6-2, 6-3 victory in two hours and 14 minutes.

It was a disappointment for Shang, 20, who had produced a stirring four-set victory over former top-10 player Roberto Bautista-Agut in the first round.

Van de Zandschulp, a former world No.22, will next face 24-time grand slam champion Novak Djokovic, who cruised past Italian qualifier Francesco Maestrelli 6-3, 6-2, 6-2.

"I didn't know about [Maestrelli], but I don't underestimate anyone," said Djokovic, who clinched his 101st victory at the Australian Open in two hours and 15 minutes.

Fifth seed Lorenzo Musetti progressed to the last 32 along with Americans Ben Shelton and Taylor Fritz.

Three-time grand slam champion Stan Wawrinka wound back the clock with a remarkable five-set victory over qualifier Arthur Gea.

But former Australian Open finalist Stefanos Tsitsipas crashed out after a four-set loss to Tomas Machac.

Swiatek headlined the women's draw on day five and she crushed Marie Bouzkova 6-2, 6-3 in one hour and 19 minutes.

It was a significantly improved performance for the six-time grand slam champion, who had battled past Chinese qualifier Yuan Yue in a grueling first round match.

"It felt great playing today, I felt much more free than in the first round. I wanted to go for it," said Swiatek, with Bouzkova limited to just three winners.

Defending champion Madison Keys, fourth seed Amanda Anisimova, four-time grand slam winner Naomi Osaka and former Wimbledon winner Elena Rybakina also emerged victorious.

In the women's doubles, 16th seeds Guo Hanyu and France's Kristina Mladenovic had a straight-sets victory over Alycia Parks and Dayana Yastremska in the first round.

14th-seeded Jiang Xinyu and her Chinese Taipei partner Chan Hao-Ching were upset by Anna Blinkova and Kamilla Rakhimova in three sets.

In the mixed doubles, sixth-seeded Zhang Shuai and Germany's Tim Puetz comfortably beat Nicole Melichar-Martinez and Yuki Bhambri in their first round match.

Third round singles action starts on Friday with top seeds Aryna Sabalenka and Carlos Alcaraz headlining the draw.

Last year's beaten finalist Alexander Zverev, Australia's title hope Alex de Minaur and two-time grand slam champion Coco Gauff will also feature on day six.  ■