McDowell birdied four holes in a row from the 2nd and recovered from a double bogey on the 11th with four more to card a six-under-par 64 and join Malaysia's Gavin Green at the top of the leaderboard.

Henrik Stenson, Sebastian Soderberg, Adri Arnaus, Victor Perez and Jhonattan Vegas are a shot off the lead after rounds of 65.

Australian Lucas Herbert is tied 14th, three shots off the lead on three-under-par, as part of a six-strong group which includes Mickelson.

Victoria native Herbert claimed his first European victory on Sunday by winning the Dubai Desert Classic at the Emirates Golf Club.

Queenslander Scott Hend is two shots behind Herbert, while Maverick Antcliff is even par and David Micheluzzi is tied for 81st at two over).

Min Woo Lee (T111, four over) and Wade Ormsby (T127, six over) will have to play very well to make the cut.

McDowell told Sky Sports: "It feels good. I got off to a fast start which was huge before the wind got up. You know it's going to blow in the afternoons and it was nice to get out of there with six-under par because I felt like I played great today.

Green shares the lead with McDowell. PHOTO: Ross Kinnaird/Getty Images.

"It would have been a horrible round to let get away but to finish birdie, birdie, birdie was nice – just feeding off Phil there who had seven birdies on the back nine.

"It was 'Phil the Thrill' there, it was fun to watch and fun to play with him."

Mickelson, who has slipped to 86th in the world rankings, was two-over par at the turn but carded seven birdies and a bogey in a back nine of 29.

The five-time major winner made just one par from the 8th hole onwards and five in total.

Mickelson will be eligible for the Champions Tour when he turns 50 in June, but appears intent on competing on the PGA Tour and European Tour for as long as possible.

World No.1 Brooks Koepka birdied the par-5 18th to card a level-par 72, while Open champion Shane Lowry made six on the same hole after his approach came to rest in rocks on the edge of a water hazard.

Lowry played the ball from the rocks but saw it roll back into the water and did well to salvage a bogey which left him five shots off the pace on one under.

- Phil Casey, PAA