Humble, TX (SportsNetwork.com) - Jordan Spieth carded a 5-under 67 in Saturday's third round and moved one stroke clear of three players at the Houston Open.

He ended 54 holes at 14-under-par 202. In his last two PGA Tour starts, Spieth has won and finished second. He will go for his third tour win on Sunday.

"I figured starting out today that the course would play tougher with this wind," Spieth said. "The hard holes would play even harder, so I put a premium on driving the ball. Drove the ball extremely well today to give myself some chances coming in."

Monday-qualifier Austin Cook managed a 2-under 70. He remained in second place and was joined at minus-13 by Scott Piercy and 2008 winner Johnson Wagner, who both shot 66 in round three on the Tournament Course at the Golf Club of Houston.

Shawn Stefani posted a 3-under 69 to end alone in fifth at 12-under-par 204. Charles Howell III (69) moved into a tie for sixth place at minus-11. He stands alongside Russell Henley, Paul Casey and Kevin Day, who all shot 68 on Saturday. Day, like Cook, fired a 64 in the Monday qualifier to get into the tournament.

Phil Mickelson, the 2011 winner, bogeyed the final three holes to fall to 8- under-par 208 after a third-round 75.

Spieth started the round three off the lead, but got off to a quick start with a 19-foot birdie effort on the first. After four straight pars, he moved to 11-under thanks to a birdie on No. 6.

Around the turn, Spieth caught fire and grabbed a share of the lead. He dropped his approach at No. 10 inside three feet and kicked that in for birdie. A 7-foot birdie putt at the 11th moved him to 13-under, where he trailed by one.

Spieth came up just short of the green with his second to the par-5 13th, but 2-putted for birdie and a share of the lead alongside Cook. Spieth's lone mistake of the day was at the 14th, where he 3-putted for bogey.

The 21-year-old made par at 15, then poured in a 41-footer for birdie on the 16th. As Spieth did that, Cook was struggling on No. 15. His drive found a hazard and that led to a double-bogey, which dropped Cook two back.

Spieth closed his round with a pair of pars.

"It means a lot. They all try to come to any event that's close to the state," Spieth said of his family. "I've got a lot of friends here as well. It would mean a lot to try and get something for them tomorrow because nobody has been there the couple that I've finished out."

Cook, who was playing in the final group with Mickelson, was solid through the front nine. He opened with a birdie at the second to go with five pars in the first six holes.

The qualifier dropped in back-to-back birdie chances at seven and eight to grab the lead at 14-under. Cook stumbled to a bogey on the 12th, but came right back with a birdie at the par-5 13th.

Cook fell two back with his double-bogey at 15. He inched back within one of the lead thanks to a 12-foot birdie putt on No. 17. Cook parred the last to end one back.

Piercy, the first-round leader, got his round going with birdies at the first and fourth. He parred the other seven holes on the front nine.

The two-time PGA Tour winner poured in three birdies in a 4-hole span from the 12th. Piercy closed a bogey-free round with a 7-foot birdie putt at the last.

Wagner got off to a hot start with three birdies in the first four holes. Back-to-back birdies at seven and eight move Wagner into a tie for the lead 12-under.

Around the turn, Wagner moved one ahead with a birdie at 11. After Cook caught fire, Wagner birdied the 15th to tie Cook at 14-under. Wagner's drive at 17 stopped on the side of a bunker. He chipped down the fairway, then knocked his third to 16 feet. Wagner 2-putted for bogey to end one behind at 13-under.

"We had a different wind today than we've had all week and I feel like I've played this golf course so many times, and I've played it well in so many different winds, so I was very happy to see a different wind," Wagner said. "I felt like it was a bit of an advantage for me."

NOTES: Spieth has had the 54-hole lead on three previous occasions, and has failed to hold all three ... Spieth has broken par in 11 consecutive rounds and has been in the 60s in seven of the 11 ... Wagner, Piercy, Cook and Stefani all could earn a spot in the Masters with a victory ... Patrick Reed had a hole-in-one on the par-3 16th, and that was the 20th ace on the PGA Tour this season.