ROME: Jelena Ostapenko stormed into the third round of the Italian Open on Tuesday with a dominant 6-2 7-5 victory over China's Zhang Shuai on a rain-delayed day in Rome.

The Latvian was at her formidable best, with Zhang unable to deal with her opponent's raw power from the baseline as she succumbed in an hour and 10 minutes in Rome.

Ostapenko, the reigning French Open champion, struck 27 winners to Zhang's 10, as she chalked up her 11th claycourt victory in her past 13 matches stretching back to last season.

The fifth seed will face either Britain's Johanna Konta or Taiwan's Hsieh Su-wei for a place in the quarter-finals.

Russia's Maria Sharapova also started with a victory, beating 16th seed Ashleigh Barty 7-5 3-6 6-2 to set up a second-round encounter with Dominika Cibulkova.

Sharapova, a three-times champion in Rome, was given a stern examination by the 22-year-old Australian, and fought her way back from 0-40 down to save serve in the decider before breaking her opponent and running away with the match.

"I think it was a really good way to end the match, to get that win, to take care of those break points when it mattered, to save the break points on my serve," Sharapova said.

"I felt like there's a lot of positives at the end of that match."

Former world number one Angelique Kerber was also made to work hard against lucky loser Zarina Diyas before prevailing 6-2 7-6(6).

Kerber, seeded 11th, was making her first return to action since retiring from the Stuttgart Open last month with a thigh strain.

"After Stuttgart it was a really tough time because I had a lot of pain in my leg, and now I can say I was without pain the whole match and I could play my game like I practiced the past few days," Kerber said after her victory.

France's Kristina Mladenovic was forced to retire due to injury while trailing Anastasija Sevastova 6-3 3-0, while defending champion Elina Svitolina barely broke a sweat as she saw off Petra Martic 6-1 6-2 to enter the last-16.