Top seed David Ferrer had to dig deep to reach the quarter-finals at the ATP Portugal Open on Wednesday finally overcoming Frenchman Eduardo Roger-Vasselin 6-4, 4-6, 6-3.
The 31-year-old Spaniard, who was beaten in his opening match at last week's Barcelona Open, will play Romanian journeyman Victor Hanescu, who accounted for sixth-seeded Frenchman Benoit Paire 7-6 (7/2), 6-4.
Ferrer, who missed the Monte Carlo Masters after injuring a thigh in the final of the Miami tournament in March, is looking to get some valuable court time prior to the French Open later this month.
The Spaniard had looked to be crusing to victory when he led by a set and 4-2 in the second but then lost his concentration.
"I lost that game and the set, In the third it was tough to break him," he said.
"It was a very good match to get through but I certainly have to lift my level for the next round. Hanescu is a good player even if I've beaten him before (he has beaten hom on both occasions they have played). I have to play well."
Ferrer, who has not played here since 2009, took nearly two hours to subdue his feisty French opponent, serving four double-faults and being broken three times.
He was brought in as a late replacement for Argentine Juan Martin Del Potro, the holder who could not play at their edition due to a stomach virus.
Despite his recent setbacks, world number four Ferrer stands a formidable 26-6 since the start of the year having won the titles in Auckland (hard) and Buenos Aires (clay) before finishing runner-up to Nadal in Acapulco on clay in February and then losing to Andy Murray in Miami.
In the women's draw, two-time grand slam winner Svetlana Kuznetsova reached her first quarter-final since the Australian Open when she beat Kazakh Galina Voskoboeva 6-4, 6-4.
Kuznetsova, ranked 45 in the world and a wild card entry, said that while she was happy to win, she was not particularly impressed with how she got through over her rival, who is ranked 117th.
"I was a little lazy at the start, it was an OK win but I'm not so happy about it. I like to play on clay but this court feels a little bit slow," she said.
The Spanish-trained Russian who now lives in her homeland but says she still needs Spanish-atyle coaching, will play Romina Oprandi, who beat China's Peng Shuai 6-1, 6-3, in the quarter-finals.
Kuznetsova has won all three meetings with the Swiss, but they last played seven years ago.
"She's got a very different game, she doesn't give you any rhythm," said the 27-year-old, who won the US Open in 2004 and Roland Garros five years later.
"She's very unpredictable and I will have to play much better than I did today."
Three of the four seeds in the women's singles advanced to the quarter-finals, led by number three Anastasia Pavlyuchenkova, coached part-time by former great Martina Hingis.
The Russian beat Spain's Estrella Cabeza Candela 6-3, 7-6 (7/4).
Fourth-seed Carla Suarez Navarro came good for Spain, beating former Portugal Open winner Yanina Wickmayer of Belgium 6-4, 6-3 while Estonia's defending champion Kaia Kanepi upset Romanian fifth seed Sorona Cirstea 6-1, 6-2.
Monica Puig of Puerto Rico ended the 2010 French Open champion Francesca Schiavone's hopes of a second successful title, after winning in Marrakech last Sunday, as she beat the Italian 6-3, 6-2.