Mickelson carded a third successive round under 70

THIRD ROUND LEADERBOARD:
(US unless stated)
-13 Phil Mickelson
-12 Padraig Harrington (Ire)
-11 Rich Beem
-10 Robert Allenby (Aus), Charles Howell III

Phil Mickelson edged ahead of Padraig Harrington at the top of the Nissan Open leaderboard after shooting a 69 to lie 13 under after three rounds.

Harrington moved to 12 under after a 70, with Rich Beem closing to within one shot of the Irishman with a 65.

Robert Allenby and Charles Howell III are three off the lead, with Jim Furyk, Sergio Garcia and Ernie Els well placed one shot further back.

American Mickelson is bidding for his second straight title on the PGA Tour.

But the Masters champion was left to reflect on a missed opportunity to put himself in a stronger position.

It would have been nice to get to 15 or 16 under to have taken the field out Padraig Harrington

He had started the day tied for the lead with Harrington at 11-under and two quick birdies gave him the advantage.

But sitting on 15 under par after 11 holes, he conceded bogies at 12, 13 and 16 to give renewed hope to the chasing pack.

"Somewhere along the line, iron shots just weren't quite coming off," Mickelson said.

"I missed a couple of fairways early on with three-woods, and I was four-under through 11, but the longest putt I had made was three or four feet.

"I didn't hit enough iron shots close. I just kind of hung in there."

Harrington, by contrast, birdied the third but dropped a shot on the par-three sixth before a birdie on the 11th hole and a run of pars secured a round of 70.

And he also rued the squandered chance to put distance between himself and his rivals.

"I had a few opportunities," he said. "It would have been nice to get to 15 or 16 under par, so that would have taken the field out."

Harrington stayed in touch with a round of 70

Looking ahead to the final day, Mickelson added: "We have to play a good round and shoot under par - probably four or five under, I would guess.

"But there are plenty of birdie holes out there to do that."

England's David Howell, who had started the day joint fourth, struggled in his third round, shooting a two-over par 73 to slide down the leaderboard into a tie for 19th.

Beem's 65 included a hole-in-one at the 177-yard 14th and he celebrated by jumping on the roof of his new Nissan car.