Simon Dyson, the highest-ranked player in the field, took over at the top in the rain-delayed third round of the Reale Seguros Open de España in Seville.
There was a delay of nearly two hours to clear flooded greens and bunkers, but then six-time European Tour winner Dyson showed his class.
After failing to get up and down from sand on the first the 34 year old World Number 36 birdied the second, fourth and fifth while others struggled.
Overnight leader Gregory Bourdy three-putted the first and third, Dyson's compatriot Robert Rock bogeyed the opening three holes and 19 year old Italian Matteo Manassero, also four under when he resumed, bogeyed the second and dropped three more strokes at the fourth after driving into a bush.
On six under par Dyson led by a stroke from Spain's Challenge Tour graduate Jorge Campillo and by two from Bourdy, Dane Søren Kjeldsen - a former winner on the course - and another of the home contingent, Pablo Larrazabal.
Dyson sank par putts of seven and 10 feet at the seventh and ninth, so turned in a fine 34.
He was still one in front, but it was now Larrazabal - third last year - who had become his closest challenger after a superb chip on the long 13th brought him his fourth birdie in six holes.
Campillo three-putted the eighth to be in third, with Bourdy and Ireland's Peter Lawrie tied for fourth three strokes behind.
Dyson almost spun his approach to the tenth into the hole and after tapping in for another birdie scrambled pars on the next two thanks to putts of 15 and eight feet.
He was seven under and went three clear when Larrazabal bogeyed the last for a 69.
