Valderrama - Scotland's Richie Ramsay led the Andalucia Masters by two shots on Thursday, but Sergio Garcia, who romped to a huge Castello Masters triumph last weekend, was waiting to pounce.
Ramsay, the 28-year-old Scot, fired a six under par 65 and to lead by two from England's Ross Fisher.
Garcia, fresh from his 11-shot victory at Castellon four days ago, carded a one-under to be five off the pace after the first round.
"Valderrama is the kind of course that suits me," said Ramsay, who was third last weekend.
"I worked out a good game plan with my caddie about how to play it in the wind and it's always nice to have a 65 around a classic course like this because it’s had The Ryder Cup and so many great champions."
The Scot was three under at the turn and then went birdie-eagle before another gain at the 15th. His only setback was a six at the 536-yard 17th.
Garcia also eagled the 11th to go to four under, but in the end he had to settle for a one under 70.
"It was a tough day out there," said Garcia. "The course was soft because of the rain, but with this amount of wind Valderrama is always tough.
"I got to 4 under after 11, but I guess it was a good round. We had a bit of fortune on 11 with a chip-in and then we got a little bit unfortunate on 13 and 17 with the drives.
"They were actually good shots, but in Valderrama shots need not only to be good but on the perfect spot. All in all, shooting under par on this course is never a bad thing."
Leading first round scores from the Andalucia Masters at the par-71 course in Sotogrande, Spain on Thursday:
65 Richie Ramsay (Britain) 67 Ross Fisher (Britain) 68 Gregory Havret (France)
Stephen Gallacher (Britain) 70 Peter Lawrie (Ireland)
Sergio Garcia (Spain)
Scott Strange (Australia)
David Drysdale (Britain) 71 Martin Wiegele (Austria)
Miguel Angel Jimenez (Spain)
Martin Kaymer (Germany)
Francesco Molinari (Italy)
Alejandro Canizares (Spain)
Stephen Dodd (Britain)
David Lynn (Britain) 72 Peter Hanson (Sweden)
Mark Foster (Britain)
Maarten Lafeber (Netherlands)
David Howell (Britain)
Shane Lowry (Ireland)
Justin Rose (Britain)
Soren Kjeldsen (Denmark)
Ignacio Garrido (Spain) 73 Romain Wattel (France)
Simon Khan (Britain)
Graeme McDowell (Britain)
Brett Rumford (Australia)
Christian Nilsson (Sweden)
Soren Hansen (Denmark)
Oliver Wilson (Britain)
Gonzalo Fernandez-Castano (Spain)
Thomas Bjorn (Denmark)
Raphael Jacquelin (France)
Graeme Storm (Britain)
Rafael Echenique (Argentina)