South Korea's Sung Kang put himself closer to qualification for next week's Masters as he leads the Shell Houston Open by three shots going into the final round.

A first PGA Tour victory on Sunday would secure him the final spot at Augusta National and he looks in good shape, sitting at 17 under after his third round in Houston.

It was not his best 18 holes of the week, with four birdies and three bogeys, and he would only be in a share of the lead had it not been for a collapse from Rickie Fowler in his final two holes.

The American, who started seven shots behind Kang, had surged back into contention with eight birdies in his first 14 holes and he arrived at the 17th sharing the lead on 17 under.

But a bogey on the penultimate hole was followed by a double bogey on the 18th as Fowler four-putted to drop three shots in two holes.

American Russell Henley is a shot further back, with Luke List firing himself up to 12 under after carding a 65 - the best round of the day.

Englishmen Andy Sullivan and Justin Rose are on five under.