Australian No.1 Ashleigh Barty has continued her fine 2019 form by reaching the third round of the Italian Open after fighting back to beat Viktoria Kuzmova in Rome.

Eighth-seeded Barty lost the first set to her Slovakian opponent, but after banking the second, held her nerve in the decider, earning a crucial late break to wrap up a gritty 4-6 6-3 6-4 victory in two hours and six minutes.

World No.9 Barty, who won this year’s WTA Miami Open, has still to lose to a player ranked outside of the top 10 since last September.

And she maintained her cracking run on clay by firing off 33 winners against the world No.43, including 10 aces, setting up a meeting with either Switzerland’s Belinda Bencic or Kristina Mladenovic of France.

Meanwhile, Serena Williams has withdrawn from the tournament persistent knee injury which casts doubt on her participation in the French Open which begins this month.

The 37-year-old American world No.11 had been due to face sister Venus in an eagerly-awaited second-round clash in Rome.

Venus received a walkover into the third round.

Serena, a 23-times grand slam singles champion, has struggled throughout the year and completed only two matches since the Australian Open where she reached the quarter-finals.

“I must withdraw from the Italian Open due to pain in my left knee,” Williams told the WTA website.

“I’ll be concentrating on rehab and look forward to seeing you all at the French Open and next year in Rome.”

Former No. 1 Caroline Wozniacki retired due to a left leg injury after losing a first-set tiebreaker to American Danielle Collins.

Denmark’s Wozniacki, who also retired from her opening match at the Madrid Open last week, took a medical timeout at 5-2 down to receive treatment then came back to force the tiebreaker but quickly retired after losing the set.

Kristina Mladenovic brushed aside French compatriot Caroline Garcia 6-1 6-2.