Aussie trio Jason Day, Marc Leishman and Greg Chalmers sit four shots off the pace after a blustery opening round of the AT&T Byron Nelson.

Day in particular had the worst of the afternoon conditions, showing his fighting qualities that included a miracle birdie off a cart path, as wayward drives became the norm.

This week features four of the top-six players in the world. Yet at the end of day one, two players who have combined for just one top-10 finish this season are tied for the lead.

James Hahn, 83rd in the World Ranking, and Ricky Barnes, No.311, each shot 64 at the TPC Four Seasons Las Colinas on Friday morning (AEST).

Hahn, 35 and the winner of two PGA Tour events, shot a bogey-free round with three birdies on each nine. He has missed two of his last three cuts.

Barnes, 36, has yet to register a victory in his nearly decade-long PGA Tour career. The 2002 US Amateur Champion had a few close calls in 2016, but couldn’t close the deal. This season has not been kind to Barnes, who has missed 10 cuts in 19 events and earned less than $150,000.

Four players are two shots off the lead after shooting 66s, including Matt Kuchar, who is looking for his eighth win on tour and his first since 2014. He is joined by Venezuela’s Jhonattan Vegas and Americans Jason Kokrak and Cameron Triangle.

As for the marquee players, three had rounds that put them in contention. World No.1 Dustin Johnson carded a 3-under 67, while Day and Jordan Spieth had 2-under 68s. Masters champion Sergio Garcia stumbled to a 3-over 73.