He got to know Watney a lot better Saturday in the CA Championship and was even more impressed.
Watney overcame a two-shot deficit with three straight birdies early in the third round and had three strong par saves on the back nine for a 5-under 67.
Mickelson answered with three straight birdies late in the afternoon during a splendid display of driving and irons and shot 69. They wound up tied for the lead at Doral.
Even though Mickelson longed for another duel with Tiger Woods, he realizes he still has his hands full with Watney.
"There's really not any weaknesses in his game," Mickelson said. "He's already won this year and played tough down the stretch in that win, and he's a tough competitor."
They were at 16-under 200, four shots clear of anyone else.
Watney, who birdied two his last three holes to win at Torrey Pines last month, ended his streak of bogey-free golf on the Blue Monster after 46 holes and still has made only one in the tournament.
"I just wanted to go out there today and really get into my round and not worry too much about the scoreboard or playing against Phil directly," Watney said. "So I'm pleased with the way I handled it."
Watney has not played in a final group before so many fans, but he has seen what it is like. He was a rookie in 2005 when Doral resembled a rock concert with Woods and Mickelson in the last group, and Woods rallying to win.
"I would love to have that opportunity," Watney said. "Maybe I'll get that shot tomorrow."
Woods won't be part of the equation.
In his first stroke-play event since winning the U.S. Open in June a week before knee surgery, Woods was thrilled with how he hit the ball, disgusted with how he putted. He managed only a 68 and was nine shots behind.
"The best I've hit it in a long time," Woods said. "Granted, I haven't played in a long time, but still."
Mickelson, the best player to have never won a World Golf Championship, is not ready to consider Sunday another duel at Doral. Jeev Milkha Singh (68) and Camilo Villegas (69) were at 12-under 204, while the group another shot behind included former Doral winner Jim Furyk (69), Kenny Perry (71) and Alvaro Quiros (69), a big hitter from Spain.
"Nick and I need to play well to separate ourselves from the rest of the field," Mickelson said.
Lefty worried he might fall behind when he made the turn in only 35 on another good day for scoring. But he hit his stride, going eight consecutive holes with birdie putts inside 12 feet. He converted only three of them.
The easiest came at the par-3 13th, when Mickelson hit 5-iron to the green and watched it roll toward the cup. The glare kept him from seeing the ball bounce lightly off the middle of the pin and stop a foot away, but the wild cheer filled him in.
"I thought after the first bounce it was going to be pretty good," he said.
Watney made a terrific par save from an awkward stance in the bunker on the the 13th, and he made another solid bunker save on the par-3 15th when Mickelson hit his tee shot to 6 feet. It looked as though Lefty would go three shots ahead until he missed the putt, and Watney caught him two holes later -- his birdie on the 16th, Mickelson's one wild drive on the 17th leading to bogey.
Watney finished with another solid par save after an approach flirted with the water on the 18th. From deep rough, he popped it out to 3 feet and stayed tied for the lead when Mickelson missed a 15-foot birdie.
Rory McIlroy, the 19-year-old from Northern Ireland who is down to his last week with a chance at becoming the youngest winner in PGA Tour history, was in the mix until struggling from the rough and making three bogeys over his last five holes.
He was at 10-under 206, six shots behind.
"It looks like it's going to be a bit of a two-horse race," McIlroy said. "But if I can go out and shoot in the mid-60s and get myself as high up the leaderboard as possible, then it will have been another good week."
Woods feels he's making progress, too.
It was his best round since his return to competition, at least until he got on the green. He missed three putts inside 10 feet, and his final birdie came on the 16th when he holed out from a back bunker.
But it was the finish that lifted his mood.
From the edge of the water, with the ball above his feet and the wind in his face, Woods hit a sweeping draw with a 3-iron from 207 yards away that caught the ridge and rolled just past the cup, settling 12 feet away.
He missed the birdie putt.
"I have not controlled the golf ball that well in a very long time," Woods said. "And that was fun. I was hitting shots that I had not been able to hit before, which was such a great feeling. Unfortunately, I'm just not making any putts."
Mickelson, who won two weeks ago at Riviera, can close in on No. 1 in the world ranking by capturing his first World Golf Championship title. It will be his first time in the final group at Doral since 2005, when Woods overcame a two-shot deficit to beat him.
Woods, in a tie for 19th, is out of the picture.
But the way Saturday went along the back nine, Mickelson still doesn't expect anything to come easily.