Bill Haas is on course to defend his Northern Trust Open title after shooting a superb 64 to open a three-shot lead over the field heading into the final round.
Haas, won who the event 12 months ago after beating Phil Mickelson and Keegan Bradley in a three-man play-off, did not drop a shot as he turned in a quite superlative display at Riviera Country Club on 'moving day'.
The American's round was three shots better than any other player managed on Saturday and ensured he finished the day at 12-under-par with a commanding advantage over his nearest challengers - compatriots Webb Simpson (68) and John Merrick (70) and South Africa's Charl Schwartzel (68).
England's Luke Donald is a further shot back on eight-under, along with Sweden's Freddie Jacobson (72), after an up-and-down round of 70 that featured five birdies and four bogeys.
Sergio Garcia of Spain is on six-under after a round of 69, but Lee Westwood's chances of contending are over following a 74 that leaves him nine shots off the pace.
After a steady start, Haas - who began his round four behind the overnight leaders - made three birdies in five holes from the fifth to move up the leaderboard, but it was at the start of the back nine that he made the most telling move.
At the short par-four 10th hole he chipped in from 20 yards for eagle and then followed it by getting up and down from a greenside bunker at the par-five 11th for a birdie to move clear.
A further birdie followed at 17 after another exquisite bunker shot and things could have been even better had a seven-footer for birdie at the last not just crept past the hole.
"It was very difficult to get to some pins and I made some great up and downs out there and par-saves to keep the round going and obviously the chip-in at 10 was a huge bonus," Haas said afterwards.
"It is nice to come back after winning last year, you hear a lot of people yelling 'do it again' and it gives you good mojo. Hopefully tomorrow will be a little more of the same."
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