Phil Mickelson leads on Champions Tour debut

The five-time major champion is one shot ahead of Australian David McKenzie, and three ahead of a chasing back of four, which includes South Korean K.J. Choi.

Vijay Singh and Ernie Els both sit at six-under.

Mickelson became eligible for the Champions circuit when he turned 50 in June but did not plan to play until he missed the cut at the Northern Trust at TPC Boston, which meant his was eliminated from the FedEx Cup Playoffs.

In his opening Champions Tour round the three-time Masters winner was grouped with Steve Stricker and Retief Goosen and fired home 11 birdies, including three on the par-fives at Ozarks National.

A back nine of 29 capped off a great start for Mickelson, who is bidding to become the 20th player to win on his Champions Tour debut.

Mickelson said: “I was a little nervous. I wanted to come out and play well"

I’ve been playing really well at home and I get out on tour and I’m playing tight, not letting myself go and swing free and aggressively. I get a little steery.

"To come out here and compete, it gives me a chance to work on that.”