(Reuters) - Justin Thomas overpowered Waialae Country Club over the previous two days but his patience was tested early in the third round on Saturday before he caught fire to stretch his overnight lead to seven shots at the Sony Open in Honolulu, Hawaii.

The American parred the first eight holes before he finally clicked into gear with consecutive birdies, followed by a strong finish as he carded a five-under-par 65 for a 22-under total of 188 in the PGA Tour's first full-field event of the year.

His aggregate of 188 tied the record low for 54 holes on the PGA Tour, set by Steve Stricker at the 2010 John Deere Classic.

"Just patience," the long-hitting 23-year-old told Golf Channel when asked what had been the key to his bogey-free round. "I didn't hit my iron shots as well I felt like today as I did the first two days.

"I had a lot of scoring opportunities and scoring clubs, I just hit really poor iron shots to 25-30 feet. But it was great. I managed my day really well and to shoot five-under not having my best stuff was great. And going bogey-free was awesome."

Thomas, who opened with a magical 11-under 59 at Waialae to take control of the tournament, is seeking his third victory of the young season, and a second in a row, and will head into the final round seven clear of fellow American Zach Johnson (65).

England's Olympic champion Justin Rose (66) is a further stroke back at 14-under, level with Americans Gary Woodland (68) and Hudson Swafford (66).

American journeyman Kevin Kisner, who made the cut right on the number, narrowly missed a 10-foot eagle putt on his final hole that would have earned him a 59 and settled for a 60 that left him nine shots off the pace.

Thomas, five strokes clear overnight after setting a PGA Tour record low for 36 holes with a 17-under total of 123, had to wait until the par-five ninth before he picked up his first shot of the day with a comfortable two-putt from range.

He then birdied the driveable par-four 10th, getting up and down from a greenside bunker, and the par-four 14th, where he hit a superb second shot from the right rough to within three feet of the cup, to extend his lead to six strokes.

Thomas also birdied the 16th, draining a 10-footer, and the par-five last, where he missed the fairway off the tee and clipped palm trees fronds with his second shot before hitting a wedge to 14 feet and sinking the putt.

"I just have to go out and do what I did today," Thomas said of Sunday's final round. "I played with a big lead today and felt like I handled it pretty well."

(Reporting by Mark Lamport-Stokes in St. Augustine, Florida; Editing by Peter Rutherford/John O'Brien)