The 31-year-old Englishman, embarking on his second full season on the world's biggest circuit, shot a five-under-par 67 to vault into contention at Riviera Country Club.

Howell is determined to give himself as many chances as he can to claim a maiden title in the U.S. and his bogey-free display in calm conditions left him four strokes off the first-round pace.

"I'm certainly pleased with the score," the world number 17 told reporters after climbing into a five-way tie for fifth place in his first PGA Tour appearance of the year.

"I got about as much out of my round as I could, to be honest. I felt I was playing all right but I missed a fair number of greens out there. However, I putted well and scored well generally."

A four-times winner on the European Tour, Howell has adopted a patient approach in his bid to shine in the U.S.

"It was the first year of my full card last year, so I am still learning my way around all of these courses," he said. "There are many I still haven't visited.

LOCAL KNOWLEDGE

"As the years tick by, I would hope, with a bit of local knowledge and a bit more experience, I will eventually give myself those chances. I'm fairly patient on that front.

"I have probably so far played my best golf in Europe. I haven't given myself too many opportunities to win tournaments over here.

"One of my goals this year was to give myself some serious chances to win out here. I need to put myself into the mix with nine holes to go, which I regularly did the last two or three seasons in Europe."

Howell, whose best finish on the PGA Tour was third place at the 2004 WGC-American Express Championship in Ireland, knows he faces an uphill task.

"It's very difficult to win out here, as we know," said the Swindon-born player, who made his biggest impact by holding off Tiger Woods to win the Champions tournament in China in late 2005.

"The likes of Colin (Montgomerie), he's had a wonderful career, a career I can only dream of, and yet he has never managed to win a 72-hole strokeplay tournament over here."

Briton Montgomerie, the European number one for eight seasons, came closest to a PGA Tour breakthrough with runner-up spots at the 1995 PGA Championship at Riviera, the 1997 U.S. Open and the 2005 British Open.