Updated

Ricky Barnes birdied six of the last eight holes Thursday at rain-softened TPC Louisiana to take a one-stroke lead in the Zurich Classic.

Barnes finished the opening round with an eagle, seven birdies and a bogey for an 8-under 64. Boo Weekley and Lucas Glover were a stroke back, and D.A. Points and Morgan Hoffmann shot 66.

Guan Tianlang, the 14-year-old Chinese amateur playing on a sponsor exemption, opened with an even-par 72, highlighted by a 5-wood that he hit to a foot on the par-3 17th. He tied for 58th in the Masters after becoming the youngest player to make the cut at Augusta National, and said Thursday that he will play in a U.S. Open qualifier in two weeks in Dallas.

Defending champion Jason Duffner shot 70, and 2011 winner Bubba Watson had a 73. They played alongside 2007 Zurich winner Nick Watney (69).

Ernie Els and Rickie Fowler topped the group at 67.

Eighty-four players were at 1 under or better, with 30 players within 4 shots of the lead. Heavy rain that spawned at least two tornadoes in the New Orleans area Wednesday left the course's normally firm greens soft and defenseless, and led to a first-round scoring average of 71.33, a half-shot better than a year ago.

Barnes has missed the cuts in seven of his last eight events. He jumpstarted his round with the eagle on the par-5 second hole, hitting a 3-wood from 294 yards to 12 feet.

Barnes, whose wife gave birth to a daughter Monday, birdied the par-5 11th, had four consecutive birdies on Nos. 13-16 and finished with a birdie on the par-5 18th. He hit all 14 fairways in regulation and had 26 putts.

The stage might be set for another Barnes-Glover shootout, similar to the 2009 U.S. Open at Bethpage in New York when the duo battled in the final three rounds. Glover eventually overtook Barnes in the final round to win his only major championship.

Glover birdied his first four holes, playing the back nine first, to get to 6 under. After a bogey on the sixth, he closed with consecutive birdies on the eighth and ninth holes to close out his round.

Weekley, fighting a sinus infection, made a 27-foot putt on the final hole to climb into a tie for second.