Phil Mickelson heads into this week's Waste Management Open in Phoenix still looking for his first victory in almost a year.

The four-time major champion's last win was at the Masters in April, but he insists he is close to a return to the winner's enclosure.

Mickelson was runner-up by a shot to Bubba Watson at last week's Farmers Insurance Open in San Diego and heads to Phoenix in upbeat mood.

"I'm excited because I can tell that my game's coming around," he said.

"I'm kind of done making changes. I'm trying to hit shots now - I'm trying to hit draws, hooks, slices, fades and see if I can get it close."

Mickelson will play alongside his fellow left-hander Watson this week in the tournament that is traditionally the best-attended - and noisiest - on the PGA Tour.

The Tour's new sensation Jhonattan Vegas is also in action this week, in the group behind Mickelson and Watson that also includes fellow South Americans Camilo Villegas and Angel Cabrera.

Dream

Rookie Vegas, the first Venezuelan to earn a PGA Tour card, has finished first and third the past two weeks and in his first-ever round with Tiger Woods, beat the 14-time major champion by five shots.

The 26-year-old is top of the money list with over $1.2million, first on the FedEx Cup points standings and up from 187th in the world to 69th. As he says himself; "it's been a dream come true - I'm just loving it."

There could be lengthy frost delays at the start of the tournament with ground and air temperatures plummeting to extreme levels in the desert.

Wednesday's pro-am had to be cancelled and PGA Tour referee Slugger White said: "It doesn't look good tomorrow morning - it's supposed to be colder - and it might be even colder on Friday.

"I've talked to people that grew up here and they've never seen it like this. Obviously we've had frost delays before, but usually that's an hour or so.

"We've got 20 to 30-mph winds out there with a wind chill factor of about 30 right now."