SAINT-QUENTIN-EN-YVELINES, France - Thongchai Jaidee of Thailand posted a 3-under round of 68 on Saturday to move 8 under and take a two-shot lead heading into the final round of the French Open.
Northern Irishman Rory McIlroy and South Korea's Wang Jeung-hun posted 1-under 70s, having been level with Jaidee and two other players overnight.
Jaidee played consistently with three birdies.
''I had a good game plan today ... hit a lot of fairway,'' the 46-year-old Jaidee said. ''Three-under is an amazing round with the conditions and the wind gusting.''
By contrast, McIlroy's third round was hugely erratic as the four-time major winner had six birdies, three bogeys and one double-bogey.
McIlroy recovered to make five birdies on the back nine.
Wang's round was the opposite, featuring three bogeys on his way back to the clubhouse after he had set out with four birdies on the front nine.
Defending champion Bernd Wiesberger of Austria posted 70 and is one shot behind at 5-under, followed by South African Brandon Stone and four other players at 3-under.
Wiesberger is looking to become the sixth player to successfully defend the title at the Le Golf National course, which is hosting the 2018 Ryder Cup.
''I'm right up there,'' said Wiesberger, who recovered from a bogey-bogey start to make three birdies. ''I have played well on Sundays here, so everything is in place.''
Stone shared the overnight lead, but fell away with a 2-over 73 - including double bogey on the 18th hole.
Mikko Ilonen, the other overnight co-leader, fared even more badly.
The Finn hit a 4-over 75 - including a quadruple bogey on the fifth hole - to fall seven shots behind Jaidee and way out of contention.
There are four qualifying places for the British Open up for grabs. They will go to the leading four players, not otherwise exempt, who finish in the top 12 and ties.