Wyndham Clark heads the field at the Phoenix Open with Seamus Power seven back

Wyndham Clark carded a flawless 64 to take a one-shot lead after the opening round of the Waste Management Phoenix Open.

The American opened with a birdie and added another two on holes eight and nine.

His momentum continued after the turn with another pair of birdies before capping off his round by picking up shots on the 13th and 15th.

Speaking after the round, Clark told reporters: "You can't necessarily control the score and what happens to your golf ball, but you can control your thoughts.

"So it was a good reminder for me to get back to, hey, when I'm playing my best, I look at the glass more half full than I do half empty."

His seven under-par round puts him one shot in front of the chasing duo of compatriots Taylor Moore and Lee Hodges.

Two-time major champion Justin Thomas is among a group of six players sitting a shot further back.

Ireland's Seamus Power is seven shots off the summit after an opening 71.

A triple bogey on the par-4 18th proved costly for the Waterford native who had birdied 13, 14 and 16.

Round one play will continue on Friday morning after play was suspended due to darkness.

Additional reporting: PA