England’s Ian Poulter also shot 66 to leap into contention on seven under, but for the second day running Kenny Perry faltered late on, just as he had when on track for Masters glory two weeks ago.

Kelly’s form was in total contrast to his performance at the Verizon Heritage tournament, where he dropped five strokes in the first five holes of his second round before running up his quintuple bogey.

A PGA Tour media official said the player had been battling an illness all week and “just couldn’t take it any more.”

After coming home in 32 today Kelly explained: “Dislocated rib, then I got the flu. It’s a different week, you feel different and that’s the way it is.

“The (physio) guys in the trailer did a great job on me and I didn’t have to medicate myself.

“The pain was right where it connects to the spine – nasty, not fun.

“I’m coming off just a bad few years it seems like. It never seemed to really fall together. I’d get an injury, I’d get sick. Getting old, it’s tough.”

Poulter, joint 20th at The Masters, went to the turn in 32 with birdies at the first, second, fifth and seventh, then sank putts of 20 and 16 feet at the 11th and 15th to move further through the field.

After starting the day down in 56th place he was up to joint sixth, but half the field had still to complete their second rounds.

They included overnight leader Charlie Wi and the Korean resumed with back-to-back birdies to improve to eight under and joint fourth with David Toms.

Perry, who bogeyed two of his last four holes in his first round 69, climbed to eight under on his return, but three-putted the eighth and then went in the water for a closing double bogey at the short ninth.

England’s Greg Owen returned a 68 to stand six under, but fellow countryman Justin Rose and Scot Martin Laird fell back from four under to two under over the opening stretch as the wind picked up in the afternoon.