Australia's Matt Jones started and ended his round with a birdie to join Bubba Watson at the top of the Waste Management Phoenix Open leaderboard heading into the weekend.
Jones carded a second straight six-under round of 65 to sit alongside American Watson - who shot a 66 - on 12 under overall, two clear of another Australian, Greg Chalmers, and Harris English.
Three birdies in the opening four holes got Jones off and running, but he played the next eight holes one-over-par until he closed by picking up another four shots in the last six holes.
Watson, meanwhile, mixed seven birdies with a couple of bogeys to maintain his good form from the opening day.
Jones, an early starter, felt he got the best of the conditions.
"We definitely got the good side of the draw going early," he said on the PGA Tour's official website. "It's [getting colder] and the ball isn't going as far."
Watson, meanwhile, is eyeing his first title since the Masters in 2012.
"I feel like I should win on every golf course," he said. "I think that once you make the PGA Tour your game travels pretty well. Everything is clicking right now."
Behind Chalmers and English were Japan's Hideki Matsuyama and Americans Pat Perez and Kevin Stadler.
Scotland's Martin Laird was the leading European on seven under, while defending champion Phil Mickelson - who shrugged off a back injury to play - improved on his level-par opening round to finish the day four under.
Mickelson, who shot a 60 on his way to winning the title last year, said: "I don't know if I'm too far back or not, but on this golf course you can really make some fireworks happen."
With a handful of players still to finish their second rounds, a number of big names were set to miss the projected cut of one under.
Among them were Padraig Harrington and Lee Westwood, who were even, and Ian Poulter at two over.