The short Donald Ross-designed Sedgefield course has only two par-fives, and Garcia made short work of both, reaching the green with five-iron approach shots and rolling in respective putts of 30 feet at the fifth and five feet at the 15th.
Riley birdied three of the first five holes and four of the final six for a bogey-free round.
Riley, 35, played on the US Ryder Cup team in 2004, but his game subsequently went into a tailspin and he has been on-and-off the Tour since.
Meanwhile, 16-year-old amateur Justin Thomas is expected to become the third-youngest player to make a cut at a PGA Tour event after shooting 72 for a three-under 137.
The Kentucky native qualified to play in Greensboro by winning a local American Junior Golf Association tournament.
Thomas is aged 16 years and three months. Bob Panasik was 15 years and eight months when he made the cut at the 1957 Canadian Open, while Tadd Fujikawa was 16 years and four days old when he made the cut at the 2007 Sony Open in Hawaii.
■DUTCH OPEN
AFP, ZANDVOORT, NETHERLANDS
Defending champion Darren Clarke of Northern Ireland carded a second round 67 to share the halfway lead of the Dutch Open with Swede Peter Hedblom on Friday.
Clarke, who won by four shots last year, is aiming to be the first man to retain the title since American Bob Byman in 1978 and he looked in good form on Friday.
After mixing three birdies with three bogeys on the front nine, Clarke came home in 31 by picking up strokes on the 10th, 12th and 15th.
Hedblom joined Clarke on eight-under for the tournament with his second successive 66.
Clarke and Hedblom are a shot ahead of Kenneth Ferrie, Bradley Dredge, Peter Lawrie, Oskar Henningsson and Wade Ormsby. First round leaders Paul McGinley and Gary Orr both slipped back. McGinley had a 70 to remain six-under and Orr’s 73 put him five behind.
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