Peter Hanson has five shots to make up as Ben Martin put himself on course for a first US PGA Tour title after establishing a three shot lead at the Zurich Classic of New Orleans.
The American recorded a course record 62 in his first round and followed that with a 67 to sit on 15 under, three shots clear of countryman Andrew Svoboda going into the weekend.
The 26 year old, who began his second round on the back nine, looked as if he was going to have an even greater lead after registering a birdie on the tenth and an eagle at the par five 11th.
Another birdie followed on 13 but Martin dropped a shot on 17 before a double-bogey on the next saw him turn in 35.
He came back in 32, though, after picking up shots on one, four, seven and nine and is now in a prime position to challenge for a maiden title.
Svoboda followed a first round 64 with a 68 to sit on 12 under, one shot clear of Korea's Noh Seung-yul who followed up his opening 65 with a flawless 68 and American Robert Streb who went round in 66.
Another American, Erik Compton, was on ten under after shooting a 68 alongside Sweden's Hanson, who led the European challenge after a second round 69.
Former Open Champion David Duval continued his resurgence this week by following up his opening 68 with a 69 to sit seven under alongside South Africa's Retief Goosen who shot a sparkling 65.
England's Justin Rose was a further shot back after a 67, one clear of countryman Paul Casey, while Padraig Harrington just made the cut at two under after a level par 72.
