Defending champion Jelena Jankovic had an easy ride to the quarterfinals of the Italian Open after her opponent was taken ill, while Ana Ivanovic squandered a four-game lead in the decisive set to lose 6-1, 3-6, 6-4 to Poland's Agnieszka Radwanska.

Ivanovic, the French Open champion and fifth seed here, started off poorly and couldn't hold serve in the first set. But the Serb began dictating play with precise groundstrokes in the second, and appeared headed toward victory as she jumped to a 4-0 lead in the final set.

Radwanska thought otherwise. Playing solid and consistent tennis, the 20-year-old won the last six games, ending the match with one of her 19 winners.

Ivanovic was more aggressive, and in the end had 31 winners. But she also committed 32 unforced errors - 20 more than her opponent.

By contrast, Jankovic was in impressive form and was leading 6-1, 1-0 when Kateryna Bondarenko of Ukraine called for the trainer and then pulled out. The two players had been on court for 35 minutes.

The 24-year-old Serb has won the Italian Open for the past two years and is looking to regain her best form after a slump at the start of the year.