After falling a set behind, fourth seed Gonzalez, ranked almost 150 places higher than the 22-year-old left-hander, looked to have clawed his way back into the match by winning the second-set tiebreak 10-8.

But Ramos-Vinolas responded to the roars of support from the local fans to grab one crucial break of serve in the decider and set up a last-16 clash with Lativa's Ernests Gulbis.

A minute's silence was observed before David Ferrer's match against Spanish compatriot Marcel Granollers following the death of former International Olympic Committee (IOC) president Juan Antonio Samaranch.

A Barcelona native, the 89-year-old was a member of the club where the tournament is being held.

Eighth seed Ferrer beat Granollers 7-5, 6-4 and Juan Carlos Ferrero also went through when his Ukrainian opponent Sergiy Stakhovsky retired. The Spaniard was leading 6-3, 4-2.

"I have a good feeling and the truth is I am playing some solid tennis," said the in-form Ferrero. "With (Rafael) Nadal out it means things are a bit more open."  Nadal, who has triumphed in Barcelona for the past five years, opted to skip the event to give his body a rest.

Lleyton Hewitt, however, will not be around to take advantage of Nadal's absence as his comeback from hip surgery stalled when he lost 7-6, 6-4 to Eduardo Schwank.

The 29-year-old Australian, who has played only one tournament since the operation at the end of January, was twice broken by the 59th-ranked Argentine and misses out on a possible last-eight clash with French Open runner-up Robin Soderling.

French third seed Jo-Wilfried Tsonga bounced Czech Jan Hajek 6-3 6-2 and will next play Spanish 15th seed Nicolas Almagro, whom he defeated last week in Monte Carlo.

"I beat him last week, but I was playing at home," Tsonga said at a news conference. "This time it is him who is at home, and he's going to get a lot of support, so I'm going to have to play a very solid match."  World number nine Fernando Verdasco, whom Nadal thrashed in Sunday's Monte Carlo final, knocked out Tsonga's compatriot Richard Gasquet 7-5, 6-3.
 

Meantime, Venus Williams will not play for the US in the Fed Cup semifinals against Russia this weekend, joining her sister Serena on the sidelines.

US captain Mary Joe Fernandez said Williams told her of the decision Wednesday morning. Fernandez had been holding out a spot for the matches, hoping at least one of the sisters would recover from leg problems in time to compete.

Fernandez said Wednesday that Venus did everything she could to get ready but is just “not quite there.” She wore wraps on both legs in the tournament final April 3 in Key Biscayne, Fla.

The team includes Melanie Oudin, Bethanie Mattek-Sands and Liezel Huber. Fernandez will fill the final spot with Christina McHale or Sloane Stephens.