Russia's Maria Sharapova battled past Denmark's Caroline Wozniacki to move into the Italian Open quarter-finals with a 6-4, 7-6 win on Thursday.
American fifth seed Serena Williams tamed lively Italian wildcard Sara Errani 6-4, 6-3 to join Sharapova in the last eight, while title holder Jelena Jankovic strolled past Russia's Maria Kirilenko 6-1, 6-1.
Sharapova, heading the queue to become world number one next week after Belgian Justine Henin retired from tennis on Wednesday, found herself in another fight having scraped past Slovak Dominika Cibulkova in three sets on Wednesday.
The Australian Open champion gained an early edge, sealing a break in the third game with a cross court backhand winner. The Dane hit back in the middle of the first set but Sharapova soon regained the advantage and served out with some big forehands.
The Russian then produced a remarkable recovery in the second set, winning five consecutive games to haul herself back from 5-1 down. She failed to hold when serving for the match but edged home in the tiebreak.
Williams twice came back from a break down in the first set before taking Errani's serve in the final game with the help of two big smashes and a net-cord winner.
Italy's last hope in the tournament also proved a worthy opponent in the second set, when former world number one Williams again recovered to clinch the match.
Serbian fourth seed Jankovic played assured tennis, mixing her strokes well, but Kirilenko made some careless errors and at one stage blasted a ball into the stands in frustration.
"I was very focused from the beginning. I played quite aggressively and I'm very pleased with the performance," the Serb told a news conference, adding she is battling illness.
"I've been sick for a week and I've been struggling a little. I have problems breathing. I'm still on antibiotics."
Sharapova will play Patty Schnyder in the quarter-finals after the Swiss ninth seed clinched a fine tussle with eighth-seeded Frenchwoman Marion Bartoli 4-6, 6-4, 7-6.
Bulgarian qualifier Tsvetana Pironkova, who stunned Serbian top seed Ana Ivanovic on Wednesday, also progressed after Belarussian Victoria Azarenka retired with a knee injury from their third round match when the former was 6-2, 1-0 up.
Serena's sister Venus Williams, seeded seven, takes on Russian 10th seed Vera Zvonareva in the late match with the winner facing Jankovic in the last eight.
