Stewart Cink and Bill Haas manoeuvred themselves to the front of the field heading into the final day of the Shell Houston Open.
Cink carded a four-under 68 and Haas a 67 as the pair moved to 11 under overall, but with another 13 men within two shots of them, the final round promises to be exciting.
Overnight leader Steve Wheatcroft was one of four men on 10 under, alongside fellow Americans Ben Crane, DA Points and Jason Kokrak, while England's Lee Westwood went round in 67 to head a group of nine at nine under.
World number two Rory McIlroy, meanwhile, went under par for a second straight round and, although he remained nine shots off the lead at two under, there were signs things were improving with the Masters on the horizon.
But it is the top of the leaderboard where attention will be focused on the final day, with a nervy final round in prospect. "Tomorrow you're going to have to play very well," Haas told www.pgatour.com. "You can't just hang on and hope everybody else will fall back."
Haas carded seven birdies against two bogeys, while Cink dropped just one shot in his round, saving par on the final hole despite finding a bunker.
Wheatcroft could only go level after back-to-back 67s, although he would have had a share of the lead had he not made a mess of a bunker shot on the 18th.
The sight of an improving Westwood, who sat level with the likes of Louis Oosthuizen, Angel Cabrera and Keegan Bradley, is bound to worry the leaders. The Yorkshireman has bemoaned his poor form on par-five holes this year, but found his range on Saturday.
"I played much more solid today," said Westwood. "I played the par fives in three under par. The first day I was one over. You can't afford to do that.
"Today, it was obviously a lot better. I'll shoot lower scores if I start playing the par-fives better."