Smith, though, would impressively play his last five holes in 1 under par to keep his hopes of a first PGA Tour title well and truly alive as he heads into tomorrow's final round just two behind Chappell. Chappell's front nine was a roller coaster with three birdies, three bogeys, and a double-bogey, but ended the day with the lead with a much cleaner back nine. Before Chappell came down the 18th hole, Koepka had birdied the hole with a 3-foot putt to tie him.
Chappell, who is at eight-under par 208, had risen to 27th in the World Ranking last fall, but is now 38th and has had just one top 10 in 12 starts, that being a tie for seventh in the Masters in his last start.
South Africa's Branden Grace, a renowned good wind player, shot 70 to move to seven under alongside another American John Huh.
NOTES: Since 2000, seven of the 17 second-round leaders/co-leaders of the Valero Texas Open have gone on to win, including two recent past champions, Steven Bowditch (2014) and Jimmy Walker (2015).
Chappell lipped out for eagle at the 14th as he retained his outright lead, but he fell into a share at the top with Koepka when he bunkered his second to 15 and failed to get up and down.
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Chappell had nearly the same distance for his approach on 18, and he landed it past the hole to set up the winning putt. He stuck that to about three feet and made the birdie to go into the clubhouse tied with Chappell. He sank a 56-foot putt to birdie earlier at No. 6, so he 2-putted for the birdie at 17 and ran in another birdie at 18.
CHAMPIONS: Fred Funk and Jeff Sluman teamed to shoot a course-record 10-under par on Saturday to take the opening-round lead in the PGA Tour Champions' Bass Pro Shops Legends of Golf at Big Cedar Lodge at Ridgedale, Mo.
Laird looked confident when he birdied the second, but he bogeyed three of the next four holes and laboured to a three-over 75 to close on three under par.
Kenichi Kuboya of Japan beat compatriot Katsumasa Miyamoto in the first playoff hole on Sunday to win the Panasonic Open.
In all, 26 players are within five strokes of the lead heading into the final round, for which weather conditions are expected to mitigate.