AP – Australian duo Matt Jones and Greg Chalmers are hot on the heels of leaders Bubba Watson and Y.E. Yang after the first round of the Phoenix Open, as Phil Mickelson made his return from a back injury.

Watson and Yang took the round one lead after each shooting seven-under on Thursday, with the Australian pair in a group of seven just one shot behind.

Mickelson returned after withdrawing from Torrey Pines last Friday but that was the only good news for the defending champion, who finished with an even-par 71 – seven shots back from the leaders.

“My back is fine. My game was a little rusty,” Mickelson said.

In Mickelson’s victory last year, he opened with a 60 – lipping out a birdie putt on the final hole – and matched the tournament record at 28-under 256.

It was far more troublesome this time around. He had a double bogey on the par-3 12th – his third hole of the morning round – after hitting into the left-side water, before three-putting for par on the par-5 15th.

Watson and Yang shot 64, with Watson hitting birdies on four of the final six holes while Yang birdied the final two holes.

Alongside Jones and Chalmers shooting 65 are Pat Perez, Kevin Stadler, Harris English, William McGirt and Chris Kirk.

Perez had five straight birdies and seven in a nine-hole stretch.

“I knew I was going to hit it good,” Perez said. “I hit it great on the range.”

English birdied Nos. 12-15 to top the leaderboard at 8 under, but bogeyed the par-3 16th – the rowdy stadium hole – and the par-4 18th.

He hit an 8-iron over the green on the 178-yard 16th.

“I guess I was a little juiced up on that tee,” English said. “I left myself with an impossible up-and-down.”