Rose, a first-time winner in the United States at last month's Memorial Tournament, gave himself a three-shot lead going into the final round at TPC River Highlands near Hartford, the Englishman having shot a solid two-under-par 68 to back up opening rounds of 64 and 62 and reach 16 under par after 54 holes.
Rose, 29, had led by four strokes from American Kevin Sutherland after 36 holes, and after eight holes of his third round his lead had stretched to six strokes before Ben Curtis closed the gap with a 64.
"The putter dried up today and I think the longest putt I holed was at 17 from about four feet so when you have a day like that and you still get in the clubhouse two under without denting your position too much I'll take it," Rose said.
"I played really nicely today and felt pretty good all in all."
USA's Curtis is in second place on 13 under and Vaughn Taylor in third at 11 under thanks to a 67. Like Curtis, Ricky Barnes had a 64 to reach 10 under as part of a seven-way tie for fourth, joined by Zimbabwe's Brendon De Jonge (67), Australia's Matt Jones (68), Americans Bubba Watson (67), Bill Lunde (69) and US Ryder Cup captain Corey Pavin, who rallied from two bogeys on his front nine with four birdies and one bogey in his last six holes for a 69.