Simon Dyson double-bogeyed the last hole to throw the race for the Spanish Open wide open again with a round to go in Seville.
In more windy conditions and after a delay of nearly two hours because of a flooded course, the current Irish and Dutch Open champion shot a one-under-par 71 to take over at the top from Gregory Bourdy.
The Frenchman did not even break 80 as he slumped to joint 21st, but after moving three clear Dyson was furious with his finish.
He was in the back bunker for two, failed to get out and then took three more.
Dyson dropped back to five under and will resume only one ahead of Spain’s Pablo Larrazabal and Dane Soren Kjeldsen.
Victory could take the 34-year-old from York into a Ryder Cup qualifying position and increase the possibility that at least half of Jose Maria Olazabal’s side in September will be English.
Luke Donald, Lee Westwood and Justin Rose are already high up in the points race, while Ian Poulter and Paul Casey are both hoping to be in Chicago as well and Robert Rock is challenging as well.
Dyson’s day did not start well when he failed to get up and down from a bunker on the first.
But as others really struggled in the wind the highest-ranked player in the field – he is currently 36th in the world – birdied three of the next four and then added another by almost spinning his approach to the 422-yard 10th into the hole.
There were also some great scrambles for par, his new belly putter rescuing him on a number of occasions, but he then missed a two-foot putt to bogey the long 13th.
Two-putting the long 16th made amends for that, but then came the mess-up on the 18th.
Larrazabal, joint third at El Prat last May, shot 69 to take over as the leading home hope in an event celebrating its 100th anniversary this year.
The former French Open winner, who beat Sergio Garcia in a play-off for the BMW International in Munich last season, had four birdies in six holes around the turn, but dropped a shot at the last.
“Only one bogey – it’s a great round,” said Larrazabal. “I like it when the course is challenging. I don’t like it when the winner is 25 under.”
Kjeldsen, round in 71, won the Andalucian Open on the course three years ago, but that was the 36-year-old's last European Tour success.
Dyson had been tied for second at halfway with 19-year-old Italian Matteo Manassero, Rock and little-known Jorge Campillo.
The Challenge Tour graduate from Caceres north of Seville had a 73 to drop to fourth place, but Rock and Manassero both signed for 76 and fell back to joint 12th five strokes behind.