Paul Casey's nine-under-par 63 left him four shots off the lead in Cologne at the International Open on Saturday.
Spaniard Pablo Larrazabal heads the field on 17 under with eight players, including Henrik Stenson, three back.
Englishman Casey recorded his second lowest European Tour round and was clubhouse leader when rain temporarily stopped play.
"The golf course is perfect," Casey, 36, said. "It really is set up for scoring so that's what I did."
The former world number three fired nine birdies in his round at Gut Larchenhof, the joint-lowest of the tournament until Australia's Richard Green posted a 62 to sit level with second-ranked Stenson at 14 under.
Casey ended his third round at 13 under par, while Larrazabal, three-times a European Tour winner including this season's Abu Dhabi Championship, stayed bogey-free for the tournament.
He produced some excellent close-range putting and then four birdies in his last six holes to take command.
Meanwhile, fellow overnight leaders Rafa Cabrera-Bello, Emiliano Grillo and Danny Willett all lost ground.
Stenson, last season's European number one, has yet to win this year but victory would pressure Adam Scott for top spot in the world rankings.
Australian Scott, 33, became golf's new world number one last month, ending a 14-month spell at the top for Tiger Woods.
Play will begin at 06:00 BST on Sunday, with a thunderstorm forecast for later in the afternoon.