John Pak raced to the top of the first-round leaderboard after posting a score of 63 (-7). Nine golfers are currently tied for second at 4 under, with J.J. Spaun the only one currently ranked among the top 30 in the world.

On No. 10 the 2016 Charles Schwab Challenge champion sank a 28-foot birdie putt to cross over to safety. Then bogeys at No. 13 and 15 had Spieth in need of a birdie on the closing holes. He got it at No. 17, nestling his approach 6 feet from the cup and sinking the putt for a 71 to go to even-par for 36 holes.

The Charles Schwab Challenge begins Thursday at Colonial Country Club in Fort Worth, Texas. Split-tee action begins at 8 a.m. EDT. PGA Championship winner Scottie Scheffler and defending Schwab winner Davis Riley (along with Daniel Berger) go out at 1:45 p.m.

After a pedestrian opening day at the Charles Schwab Challenge, in which he made only two birdies and two bogies, and fired an even par 70, Rickie Fowler posted a marvelous second round at Colonial.