Tiger Woods and Phil Mickelson, who went head-to-head in the final round last year at the Ford Championship at Doral, are on track for a repeat performance after the second round on the Blue Monster.
Woods won 12 months ago by a stroke after a compelling duel and the pair are part of a four-way tie for the lead at the halfway stage this time.
Playing in calm morning conditions, the world number one shot a 67 while Mickelson carded 66 and their 13-under-par 131 halfway total was later matched by Scott Verplank (65) and Camilo Villegas (66).
Major championship winners David Toms and Rich Beem and surging Mark Wilson are one shot behind.
Padraig Harrington bogeyed the last to record a round of 70 that leaves him seven shots off the pace.
The cut fell at a tournament record-low of four under at 140 and 39 players had scores in red numbers but went home for the weekend, including Graeme McDowell, who finished on two under.
Woods and Mickelson quickly pointed out that it is not a two-horse race but the two stars are expected to be in the shake-up on Sunday.
"Right now, we're tied for the lead but we've got a long way to go and you've got to continue making birdies," Woods said.
"After Saturday's round, that's when I'll start thinking about going head-to-head with Woods," Mickelson said. "The first couple of days, you're not worried about where he's at, but what number it's going to take to win."
Woods drove the ball uncharacteristically straight but was not thrilled with his score as he squandered several good birdie chances.
"I feel like I hit the ball well," he said. "I just didn't make enough
putts, I didn't putt nearly as well as yesterday.
"We've got a long way to go and you've got to continue making birdies, the course is pretty receptive right now.
"You fire at the flag, it just plugs right there and you've got a makeable putt."
The duo had different takes on the easy conditions, a result of soft fairways and greens, sparse rough and little wind.
Woods would love the course to offer a greater challenge, while Mickelson likes it just the way it is.
"It hasn't really poured rain here and it's super soft," Woods said. "I know everyone wants to have the course green but that's not always necessarily the best way to have a course.
"But hey, it is what it is, you adjust and you play. I've always been more fond of US Open set-ups than where you've got to average 65 or 66 or 67 to have a chance."
