Shawn Stefani retained his lead on day two of the Tampa Bay Championship after shooting a one-under-par 70 on Friday but he's under pressure from Australian Adam Scott, who is just one stroke behind.
Stefani, though, came into his second round off the back of a six-under 65 but could not repeat the performance as he struck two bogeys to go with his three birdies at the Innisbrook Resort course in Palm Harbor, Florida.
The 31-year-old Tour rookie is just one stroke ahead of Scott and South Korean K.J. Choi, with Scott firing an impressive five-under 66 and Choi managing a 67.
Scott's round was among the best of the day with the eight-time PGA Tour winner leaping 15 places up the leaderboard after his bogey-free display.
A group of four players - Harris English, Brian Harman, Jason Dufner and Peter Tomasulo - sit a shot back in a tie for fourth at five under.
Dufner looked the most impressive of the quartet on Friday after he joined Scott in shooting a 66.
Spanish veteran Sergio Garcia is joined by Tag Ridings in a share of eighth on four under, while South African George Coetzee, American Ben Kohles and Australian Greg Chalmers are tied for 10th on three under.
Chalmers was at one over after the first nine holes but produced four birdies on his back nine to finish with three-under 68 on Friday.
Chalmers is one stroke ahead of fellow Aussie Marc Leishman, who posted a one-under 70 in his second round, while Geoff Ogilvy dropped 16 places to one under through a one-over 72 after being well in contention following the first round.
Stuart Appleby (68) and Jason Day (72) are at even par after two rounds, while Aaron Baddeley (71) is one stroke further back.