(Reuters) - Jason Dufner moved one step closer to a fourth PGA Tour victory with a sizzling back nine to grab a two-shot lead after the third round of the CareerBuilder Challenge in La Quinta, California on Saturday. The laidback American, who had been a stroke clear overnight, racked up seven birdies after the turn, including five in a row, to fire an eight-under-par 64 at La Quinta Country Club, one of three co-hosting venues this week. Taking advantage of near-perfect conditions at the pro-am event long known for its low scoring, Dufner posted a 23-under total of 193 to finish two ahead of compatriot Jamie Lovemark, who carded a 65 at the PGA West's TPC Stadium Course. More...