YE Yang and Bubba Watson have both recorded rounds of 64 to lead the Waste Management Phoenix Open after Thursday's play.
Yang, the 2009 PGA Championship winner, and Watson, the 2012 US Masters champion, both hit eight birdies on the way to a first-round effort of seven-under-par.
The duo are joined at the top of the leaderboard by a large chasing pack, with seven players all shooting 65 to sit just one shot adrift of the leaders.
Hunter Mahan and Keegan Bradley carded scores of 66, while Martin Laird and Lee Westwood are two of 14 players to finish the day on four-under-par.
