With his birdie on 18, Mickelson took a one-stroke lead over Stephen Ames and Rod Pampling.
FORT WORTH, Texas (AP) -- Phil Mickelson was already frustrated by his slow start in the third round of the Crowne Plaza Invitational.
Then he finally saw a scoreboard.
"I couldn't see the first five holes how anybody was doing," Mickelson said. "I walk up to the sixth tee and I see I'm three or four shots back. That was kind of rude awakening."
Lefty responded by hitting a perfect drive at the 394-yard 6th and then his approach to 5 feet. That was the first of his seven birdies over the closing stretch for a 5-under 65 on Saturday that kept him alone in the lead at Colonial at 12-under 198.
When he made a 17-foot birdie from the front edge of the closing hole, after the others had finished playing, Mickelson took a one-stroke lead over Rod Pampling (63) and Stephen Ames (64).
While Mickelson struggled early, with a bogey and several missed chances, Pampling and Ames got off to fast starts. Ames had three birdies in the first four holes and finished without a bogey. Pampling was 5 under through seven holes.
By time Mickelson saw the scoreboard, he was 6 under -- three strokes behind Pampling and two behind Ames.
"It was tough to be patient when I am watching guys shoot 4-or 5-under par the front nine and take off," Mickelson said. "All of a sudden I go from leading to three or four shots back. But again, I knew that I had those holes to play and if I could make some birdies and follow suit I'd be able to hopefully catch up."
Mickelson did and for the 27th time takes a lead into the final round of a tournament. He has gone on to win 19 times, including the Northern Trust Open in February, his only victory this season.
The last six Colonial champions led or were tied for the lead after 54 holes. The last time that didn't happen was 2001, when then-defending champion Mickelson and Brett Quigley were tied going into the final round before Sergio Garcia won.
Pampling was on pace for a record-tying round at Colonial, the course near the Australian native's Flower Mound home that he gets to play often, before consecutive bogeys at 16 and 17. He hit his approach at No. 18 within a foot for a birdie that left him two strokes off the tournament record.
"Still finished with a birdie," Pampling said. "The good taste is back in the mouth."
Tim Clark (64) was alone in fourth, three strokes back. Ben Crane (67), Kevin Sutherland (68) and Brian Gay (69) were at 203.
After hitting his first shot of the day into a fairway bunker and having to settle for par 5 on the opening hole, Mickelson was less than 30 yards from the flag after a 333-yard drive at No. 2. But he flubbed the chip shot, leaving it in the rough short of the green then two-putted from inside 8 feet for bogey.
When an 11-foot birdie chance at the 467-yard 3rd slid by the hole, after hitting a low-liner from the rough that rolled up near the flag, Mickelson shook his head in disbelief. The frustration didn't go away when a 24-foot birdie try at the difficult 252-yard par-3 4th stopped just short.
But he had three consecutive birdies to get to 10 under.
Mickelson hit his approach at No. 9 within 6 inches for a tap-in, the first of three consecutive birdies that got him to 10 under. He knocked his second shot at 10 to 5 feet, and blasted from a greenside bunker at the 611-yard 11th to about 4 feet.
A bogey followed at No. 12, when he decided to chip instead of putt from the front fringe and knocked it 8 feet past the cup. He saved par out of the greenside bunker at the par-3 13th by hitting inside 3 feet before two more birdies, with approach shots inside 10 feet at Nos. 14 and 15. And the closing birdie to lead alone.
"I always like having a shot in hand," Mickelson said. "I set a goal to try to shoot 4 under on the backside, and I needed that putt to do it."
Pampling rolled in 17-foot birdies at Nos. 1 and 3, then knocked his tee shot at the long par-3 inside 4 feet. When he made an 8-footer at No. 14, he was 12 under.
But Pampling caught a bit of bad luck on the par-3 16th when the green didn't hold his tee shot, then he two-putted from 19 feet after chipping back. His tee shot at the 17th was way right into the trees, through he managed to get his second shot into a greenside bunker.
"If you look at the end of the day, and were told that's what you were going to shoot, you would have been very happy," said Pampling, adding that he wasn't aware of the course record. "I was just trying to do my thing and just play golf."
Gay, whose only PGA victory came at the Mayakoba Golf Classic in February in his 293rd tournament, was leading at 10 under after his 16-foot putt at the 432-yard 7th was his fourth birdie of the round.
Gay was still bogey-free at Colonial -- through 44 holes -- until his approach at No. 9 went into a greenside bunker. He blasted inside 8 feet, but two-putted from there. He dropped another shot at par-5 11th, where he three-putted from less than 10 feet.
"I felt like I was playing pretty well. I made some mistakes that cost me," Gay said. "I still feel like I've got a chance. I just need to recharge for tomorrow."
Divots:@ First-round leader Johnson Wagner took a triple-bogey at No. 5 after he knocked his tee shot at the course's longest par-4 (472 yards) out of bounds into the trees along the Trinity River. He followed with a three-putt bogey at 6 on the way to a 73, and was nine strokes back. ... Quigley started with an eagle 3 at No. 1 when he holed a 68-foot shot from a bunker, then had two 25-foot birdies on the next two holes. His only non-par after that was a bogey at 17. He shot 67 and was at 206.