Harrington and Mickelson battle it out

Padraig Harrington and Phil Mickelson shared the lead at 11 under par after the second round of the Nissan Open in California.

Irishman Harrington, the first-round leader, shot a three-under-par 68 in his debut in this tournament. Mickelson, who last played Riviera Country Club in 2001, shot the low round of the day with a 65, which included an eagle on the 17th.

Charles Howell, who finished second at this event in 2003, also had a 65 and is at eight under for two days, three strokes behind the leaders.

Pat Perez, Sergio Garcia and English golfer David Howell are tied for fourth at seven under.

It appeared Harrington would have a two-stroke lead going into the third round when Mickelson failed to get up and down from a bunker on the par-three 16th. Mickelson though made a 14-foot eagle putt on the following hole to rein Harrington in.

"I would have thought there might be more guys up there," Harrington said after looking at the leaderboard. "It is a tough golf course though."

It is the first time Harrington has played this event and so far has taken a liking to the famed course.

"I'm happy enough," Harrington said. "It's a big tough ask to follow up a good round. Anything in the 60s was the goal."