(CNN) -- American duo Phil Mickelson and Nick Watney are four strokes clear of the field going into the final round of the WGC-CA Championship on the Blue Monster Course at Doral, Florida.
Mickelson has led for two successive rounds as a six-under-par 66 kept him on top in Florida.
World number three Mickelson carded a third-round 69 to move onto 16-under- par -- after seeing his two-shot halfway lead eroded by a 67 from Watney as the pair vied for the lead all day in the final group.
Jeev Milka Singh of India (68) and Colombia's Camilo Villegas (69) lead the chasing pack, while Jim Furyk and Kenny Perry are among a group of five players a further stroke back on 205.
Northern Ireland teenager Rory McIlroy has six shots to make up on the leaders after a disappointing end to his third round on Saturday.
McIlroy, the youngest player in the field and bidding to become the youngest tournament winner in USPGA Tour history at the age of 19 years, 10 months and 12 days, had been going well on 13-under before a run of three bogeys in four holes dropped him back to 10-under.
However, the teenager stayed composed on the final hole to make par for a round of 72 to give himself a fighting chance on the last day -- on the same mark as Australia's Rod Pampling and Justin Leonard.
"It was a pretty difficult day out there and I thought I was doing very well," McIlroy told PA Sport. "I just let a few slip at the end. It could have been better but I am still there or thereabouts."
Spain's Sergio Garcia began the tournament with an outside chance of replacing Tiger Woods as world number one but any hopes of a victory, with Woods needing to finish lower than 27th, disappeared when the world number two returned a lackluster pair of 72s.
Garcia had a better day on Saturday, shooting a 68, but Woods matched him as he eased back into his old routine in his first strokeplay event for nine months following reconstructive knee surgery. Woods shot a 68 to move to seven-under-par, nine strokes off the lead.