(Reuters) - American Robert Streb extended his lead at the RSM Classic on Saturday with another bogey-free performance, carding a three-under par 67 in the third round. Streb, who tied his career-low round with a nine-under 63 on the Plantation Course on Friday, has not made a bogey since early in the first round. The 33-year-old has a three-stroke lead going into the final round and said he might try a more aggressive approach on Sunday at Sea Island, Georgia, where he logged his first - and so far only - PGA Tour win six years ago. “I don’t think the wind’s supposed to blow quite as hard tomorrow, so probably got to make a few birdies. Guessing a few guys will go low and see how we do,” Streb said. Streb will have to fend off two-time major winner Zach Johnson (65) and his fellow American Bronson Burgoon (67), who were tied for second through 54 holes. Johnson finished strong with a trio of birdies in the final five holes.“In these conditions, when it’s windy like this, you’ve really got to control your ball,” Johnson said. “Putting with the wind I think is the most trying part. I would assume my peers would say the same.” Emiliano Grillo of Argentina finished four shots behind the leader in fourth place after a 65, while Americans Kevin Kisner (66) and Kyle Stanley (68) were tied for fifth with Colombia’s Camilo Villegas (70).