Mickelson stays one ahead after delayed first round Twice champion Phil Mickelson remained one shot in front of the chasing pack when the delayed first round of the Northern Trust Open was completed on Friday. Fresh from a dramatic victory at the Pebble Beach National Pro-Am on Sunday, Mickelson had taken control of the tournament when he chipped in to birdie his last hole for a superb five-under-par 66 on Thursday. Thirty players were still out on the course when play was suspended in fading light and, of those, American Troy Matteson made the only significant move up the leaderboard on a sun-splashed Friday morning. Matteson birdied the par-five 17th and then parred the final hole for a 68 at Riviera Country Club to share fourth place with compatriot Jonathan Byrd and Swede Carl Pettersson. Mickelson's closest pursuers were fellow Americans Hunter Mahan and big-hitting J.B. Holmes who both carded 67s late on Thursday before play was halted in the gathering gloom. Strong gusting winds at Riviera had made scoring tricky for the players but in-form Mickelson coped well with the conditions as he generally kept his ball below the tree line with low, penetrating shots. "It was a challenging day because Riviera doesn't give you great opportunities to run balls on to the green," the American world number 11 told reporters after mixing six birdies with a lone bogey. Fortunately the greens were somewhat receptive, and that's why I think the scores weren't extremely high. You could keep the ball underneath the wind, underneath the tree line and still get it to stop somewhat on the greens. Left-hander Mickelson, in pursuit of his 41st victory on the PGA Tour, was among those players who set off early on Friday morning for the second round. With limited hours of daylight at Riviera this time of year and a full field of 144, the second round is unlikely to finish on Friday. Reporting by Mark Lamport-Stokes; editng by Steve Ginsburg