Scott, the joint leader with Oosthuizen after the first round, made four birdies to keep pace on the front nine, before missing a birdie chance on the par-five ninth, which he had eagled the day before.
After positioning himself well with a deep second drive that nearly reached the green, the Australian left his chip shot short, setting up a difficult 10-foot putt. He pulled the putt wide by inches and had to settle for par.
Scott’s struggles continued on the back nine with three bogeys to go along with his three birdies. Still, he believed he could make up ground on Oosthuizen over the weekend.
“Five shots is just a couple of holes to get back,” Scott said. “There are eagle chances and there’s also a lot of trouble, so it can all turn around quickly.”
Peter Hanson and Bubba Watson fell off the pace after trailing by one coming into the day.
Hanson slipped to 12th place after carding a 71, while Watson plummeted to 17th after triple-bogeying the tricky par-five 15th and finishing with a 72.