Couples, who will captain the U.S. team at next month's Presidents Cup matches in Australia, birdied six of the first seven holes at the TPC-San Antonio course. The only hole in that stretch that he did not birdie was the par-3 fourth, where he made his double bogey.
He turned in a two-day total of 17-under 127 with Mark Calcavecchia a distant second at 134. Nick Price was alone in third at 135.
Couples is trying for his second victory of the year. His only triumph to date came at the Senior Players Championship.