Joe Durant and Lee Janzen posted rounds of 67 to take a share of the lead after the first round of the Shell Houston Open at The Woodlands in Texas yesterday. Fred Couples, Carl Paulson and Adam Scott are a shot further back at four under par.

They are followed by a group on five under that includes defending champion Robert Allenby and Chris DiMarco.

David Duval is five shots off the pace following a level-par round of 72, while Vijay Singh is a shot further back on 73.

Irishman Graeme McDowell finished towards the tail of the leaderboard after a round of 78.

McDowell, a student at the University of Alabama, received an invitation to play after winning last year's South of Ireland Amateur championship at Lahinch, which has the same sponsor.