Tiger Woods surged three shots clear at the halfway stage of the Chevron World Challenge in California after a second round of 67.
Woods had a pair of eagles in his round, both at par fives, and at one stage looked like holding an even more convincing lead, but a double bogey five at the 15th after finding water and another dropped shot at the 17th checked his progress.
His aggregate through two rounds of 136 gave Woods a three shot cushion over his fellow American Matt Kuchar, who also had a 67, and KJ Choi, who followed his opening 66 with a disappointing 73.
Zach Johnson and Hunter Mahan were tied for fourth on 140 after rounds of 67 and 68 respectively, with Rickie Fowler a further shot back after a 70.
Australian Jason Day stood seventh on two under after a 68 repaired much of the damage of his first round 74.
Woods, without a victory for two years, produced some vintage golf in his round, picking up three shots in his opening three holes thanks to an eagle three at the second and a birdie at the short third.
He had been three behind Choi at the start of the day but it was quickly becoming apparent Woods was taking control.
A dropped shot at the sixth pegged him back, but it was recovered two holes later, and Woods for the second time in his round made eagle when he tamed the long 11th, following that with back-to-back birdies.
That put Woods seven under for his round, but he could not sustain the remarkable form over the closing holes, going double-bogey, birdie, bogey from the 15th to the 17th before concluding with a par.
Woods, looking for his fifth World Challenge title, is playing well at the tournament he hosts but it not the first event he has led recently.
Three weeks ago he was ahead after two rounds of the Australian Open but a third round of 75 proved damaging as he finished third.
Kuchar had seven birdies and two bogeys in an impressive round today, while Choi's title hopes were dealt a major blow when twice went in the water and had a quadruple bogey on the 15th.
