LOS ANGELES, Feb 2 - American Jeff Quinney carded a sizzling eight-under 63 to pull four shots clear of the field midway through second round play at the Phoenix Open on Friday in Scottsdale, Arizona.

Quinney, a PGA Tour rookie who has enjoyed a red-hot start to his professional career, posting top 10 finishes in two of his first three events, mixed nine birdies with a single bogey to surge top of the leaderboard at 13-under 129.

The only blemish on Quinney's scorecard through two rounds at the TPC Scottsdale Stadium course was a bogey four at the par three seventh.

Sitting four shots back on nine-under 133 are a trio of Americans, Bubba Watson and Robert Garrigus, who signed for four-under 67s, and John Rollins with a 68.

Twice winner and world number five Phil Mickelson continued his early season woes and faces an uphill struggle if he hopes to make the projected one-under cut.

Mickelson, who has finished outside the top 40 in his only other two tournaments this season, had another sputtering start, carding bogeys on two of his opening three holes to drop to two-over.

U.S. Open champion Geoff Ogilvy of Australia is also looking at an early exit after returning an even par 71 to sit on one-over.

Fiji's Vijay Singh was working hard to make the weekend as he carded four birdies on the front nine to get to four-under.

Charles Howell III, the FedEx Cup points leader with two runner-up finishes in three tournaments this season, was among the late starters and after a bogey and three birdies in the first six holes was six-under for the tournament through eight.

Overnight leader Dudley Hart was level par through 13 to sit six shots off the pace.