Harrington had six birdies and three bogies in his round of 68

SECOND ROUND LEADERBOARD:
(US unless stated)
-11 Padraig Harrington (Irl), Phil Mickelson
-8 Charles Howell
-7 Pat Perez, Sergio Garcia (Spa), David Howell (Eng), Robert Allenby (Aus)
-5 Jim Furyk, Rocco Mediate, Aaron Baddeley, Rich Beem, Ernie Els (SA), Johnson Wagner

Padraig Harrington shot a three-under-par round of 68 to hold on to a share of the lead after the second round of the Nissan Open in California.

He is level with Phil Mickelson on 11 under, whose 65 included an eagle on the 17th at the Riviera Country Club.

Charles Howell, who finished second at the event in 2003, also carded a 65 and is at eight under, three off the lead.

Pat Perez, Spain's Sergio Garcia and Englishman David Howell are tied for fourth place on seven under.

Harrington, who was at eight under overnight, started his second round on the back nine and promptly bogeyed the 10th.

It's a lot easier to play with a big, noisy gallery Padraig Harrington

He birdied the next, then sandwiched two bogeys at 13 and 15 around a birdie at 14 as Mickelson was methodically making his way up the board.

But Harrington had back-to-back birdies at 16 and 17 to make the turn at nine-under and then picked up two further shots at the 1st and 6th coming in.

"I'm happy enough," he said. "It's always hard to follow up a good round of 63. Anything in the 60s was really the goal.

"I'm still making mental errors here and there but I made some birdies to counteract some of the bogeys."

Harrington said he was looking forward to playing in the final group with Mickelson on Saturday.

"It's a lot easier to play with a big, noisy gallery," he said. "It adds a bit of excitement."

David Howell has had a tournament-best 48 putts through the first two rounds

Mickelson, who cruised to a five-shot victory at the Pebble Beach National Pro-Am last week, was grateful for his long eagle at the penultimate hole for hauling him level with Harrington.

He said: "I just flushed my approach. It came off perfect, ended up in the middle of the green and I made the putt."

Garcia's round included five birdies and two bogeys.

"I felt better yesterday," said the Spaniard, who is making his 2007 US Tour debut.

"Although I hit some really nice shots, I was a little bit more wayward. Overall it was OK."

England's David Howell shot two birdies and two bogeys coming home to keep himself in contention for a first US Tour victory.

"I'm negotiating my way around pretty well. "I'm putting it in the right places. I had a little bit of luck go my way at times."