World number one Adam Scott produced a bogey-free third round 66 to move two shots off the lead at the Crown Plaza Invitational in Forth Worth, Texas.
The Australian is in danger of losing his place at the top of the Official World Golf Ranking after only a week, depending on how Henrik Stenson finishes at the BMW PGA Championship at Wentworth, but four birdies helped him to five-under overall to give him a fighting chance going into the final round in Texas.
His performance on Saturday showed a steady return to form after a disastrous four bogeys on the opening day put him way off the pace.
When asked if the possibility of Stenson usurping him was a concern, Scott told the PGA Tour website: "I can only worry about my golf here. Worrying about that isn't going to help me at all.
"It's all very tight. We know that. I'm happy to have gotten to number one. I hope it's not such a short stay."
Four men are tied leading the way on seven-under overall going into the final day.
Hideki Matsuyama and David Toms were the big movers at the top, hitting 64 and 65 respectively, while Chris Stroud and Chad Cambell also go into the final day sharing the lead.
Kevin Chappell heads the chasing pack one shot behind after falling short of being only the seventh player in PGA Tour history to shoot 59.
Six birdies and an eagle after 11 holes made that a possibility at one point, also giving him the overall lead, but the American was unable to sustain the momentum and finished on 63 for the day.
Chappell refused to get too downbeat after missing out on the feat, suggesting his luck just ran out slightly on the back nine.
"I used up a lot of luck today," Chappell told the PGA Tour website.
"I had two chip-ins and made some long putts. Fifty-nine would have been nice but kind of lost the feel of the putter there on the back nine. All in all, a good day."
Friday's leader Brice Garnett slipped to three-under overall after a disappointing double bogey and two bogies saw him card 74 in the third round.