Former world number one Ana Ivanovic [ Images ] showed flashes of the form that took her to the pinnacle of tennis as she upset ninth seed Victoria Azarenka [ Images ] 2-6, 7-6, 6-2 in the first round of the Cincinnati Masters on Monday.

Serb Ivanovic, a first-round casualty at San Diego last week, had appeared set for another early exit before rallying to beat the in-form Belarusian, who won the Stanford Classic earlier this month.

The 2008 French Open [ Images ] champion Ivanovic briefly held the world's top ranking that year, but a subsequent collapse in form and a series of niggling injuries have seen her ranking slip to 62nd. The Serb was joined in the second round by another fallen former top-ranked player in Russia's [ Images ] Dinara Safina [ Images ], who eased to a 7-5, 6-4 win over Italy's [ Images ] Roberta Vinci.

Safina was also forced to dig deep, rallying from 3-5 down in the opening set before closing out her fifth win against the Italian from five matches.

The 24-year-old, now ranked 35 and yet to make a semi-final this season after returning from a back injury that sidelined her for three months, will next face Belgian Kim Clijsters [ Images ].

Israeli Shahar Peer advanced after Olga Govortsova of Belarus retired when trailing 6-3, 4-1, while France's [ Images ] Marion Bartoli [ Images ] thrashed Spain's Anabel Medina Garrigues 6-4, 6-0.

Bartoli's compatriot Aravane Rezai [ Images ] was not so fortunate, however, being dumped out by Serb qualifier Bojana Jovanovski 4-6, 6-3, 6-4.