England's Ross McGowan went to the turn in a brilliant 30 strokes to take over the Madrid Masters lead.
One behind Spain's Sergio Garcia and Scot David Drysdale at halfway, the 27 year old from Surrey had an eagle and four birdies to charge to 18 under par with a putter he bought on e-bay recently.
Title favourite Garcia was two clear after opening his third round with back-to-back birdies. He picked up further shots on the fifth and eighth yet was suddenly the one doing the chasing again.
Drysdale, like McGowan searching for his first European Tour win, kept his hopes alive with a front nine 33 - but was two behind.
Low scoring was the order of the day again in the Spanish sunshine.
McGowan, who finished his second round with a 15 foot eagle putt, followed birdies on the first and fourth with a 25 footer for another eagle at the next.
Runner-up to amateur Danny Lee in Australia in February and third in Switzerland last month, the former English amateur champion then birdied the seventh and eighth as well.
Swede Niclas Fasth had already posted a 64 - and Luke Donald, who made the halfway cut with nothing to spare at four under, fired a 65.
"My goal was a couple of 64s to get to 20 under and see if it was good enough," he said.
With the way McGowan, Garcia and Drysdale were going the winning score looked likely to be a lot lower.
