ESTORIL, Portugal (AFP) - Second seed Nikolay Davydenko shrugged off a sluggish start, claiming his ninth victory in succession on Wednesday to move into the quarter-finals of the Estoril Open.
The Russian, who won the Miami title little more than a week ago over Rafael Nadal, staged a comeback to defeat Czech Ivo Minar 2-6, 6-2, 6-4 at the Estadio Nacional.
Davydenko is riding a run of form after also helping Russia into the Davis Cup semi-finals at the weekend over the Czechs.
But the Russian is unsure of his confidence as he ventures onto clay.
"I was leading 4-1 in the third set and I was not sure if I could win the match," said the player with a 22-5 record this season.
"At this moment, I don't have particularly good confidence. I need more matches on the clay."
The world number four has a hit-or-miss history in Portugal, losing three times in the first round while winning the 2003 title and playing a final two years ago.
He will on Friday face seventh seed Marc Gicquel, who beat fellow Frenchman Thierry Ascione 7-6 (7/2), 6-3.
Elsewhere in the second round, Florent Serra put a second French player into the last eight as he beat Rui Machado 7-6 (7/5), 6-1 a day after the local earned his first ATP career win as Ivo Karlovic retired injured.
Italian Flavio Cipolla upset fifth seed Gilles Simon 6-2, 5-3 as the French player retired with a back injury.
Top seed Roger Federer, who will be on court on Thursday, indicated he will be ready to ride to the Davis Cup rescue for Switzerland after the nation was drawn to face visiting Belgium in the World Group playoffs in September.
At the weekend, Stan Wawrinka led the team down the comeback road with his pair of singles wins in the 4-1 defeat of Belarus in Minsk.
That victory set the stage for Federer to come on board for the September 19-21 tie which could cement the former finalists back in the elite grouping.
"The chances are very good that I will play," Federer confirmed. "I'm proud the team could win over Belarus without me. It's a great effort.
"I'd love to get Switzerland back into the World Group. I'd say my decision is pretty much taken."
Should he need any convincing, Swiss Davis Cup coach Severin Luethi is on hand this week as part of 'Team Federer', working with the star pupil alongside Federer's new provisional coach Jose Higueras.
Switzerland and Belgium last played in Brussels in 1999, with the hosts winning and a teenaged Federer losing both of his singles matches.
Federer's way in the top half of the 32-man Estoril draw is looking clear, with the defeat of fourth seed Jarkko Nieminen eliminating any Top 50 player from Federer's side.
The Swiss is working on confidence this week as he trials Higueras, with the possibility that the 55-year-old could be brought on board for the clay season and perhaps beyond.
"I've not had too many days on clay, it will be tough to change surface for all players," said Federer, in the chase for the only grand slam to have eluded him, the French Open.
"I hope I can then get on a roll. I hope Estoril will pay off and I can do well at other events especially Roland Garros."
The women's draw lost its top seed as former semi-finalist Flavia Pennetta crashed out to Czech Iveta Benesova 6-2, 6-2.
Italian third seed Karin Knapp, February's Antwerp finalist, got a victory over Mariana Duque Marino of Colombia 6-3, 6-4 while French eighth seed Camille Pin reached the quarter-finals against Tsvetana Pironkova of Bulgaria 6-3, 6-4.
