British Open golf champion David Duval of the United States and former Masters champion Vijay Singh of Fiji headline the field at The International golf tournament beginning Thursday in Castle Rock, Colorado.

Duval is coming off his win two weeks ago at the British Open and Monday's special made-for-television event "The Battle at Bighorn" in which he and Karrie Webb of Australia lost a close match to world number one golfer Tiger Woods and Annika Sorenstam of Sweden.

Singh won consecutive European Tour titles earlier this season and has been seventh or better in eight tournaments.

Also in the field for The International are two-time tournament champion Phil Mickelson of the United States, who tied for 30th at the British Open. Two-time masters champion Jose Maria Olazabal of Spain and former British Open and PGA Champion Greg Norman of Australia are also in the field.

The International is a unique golf tournament that uses a modified Stableford scoring system that rewards aggressive play. Points are awarded on each hole rather than counting total strokes for each round, and the golfer with the highest point total wins. Zero points are awarded for a par, a birdie (one under par) is worth two points, an eagle (two under par) is worth five points, a point is subtracted from a player's score for a bogey (one over par), and three points are subtracted for a double-bogey or worse.