King Abdullah Economic City - Graeme McDowell mastered windy conditions to make three birdies in his last three holes and join fellow leader Gavin Green at six-under par in the opening round of the Saudi International on Thursday.
The 40-year-old Northern Irishman started brilliantly with four birdies in his first five holes just as the gusts arrived at Royal Greens Golf Club in King Abdullah Economic City.
The 2010 US Open winner's only mistake was a double bogey on the par-three 11th, but he bounced back with a birdie on the next before his grandstand finish took him tied top.
"I got off to a fast start which was huge, before the wind got up, which is inevitable out here in the Middle East," said McDowell.
"It was nice to get out of there with six-under par because I felt like I played great today. It would have been a horrible round to let get away, but to finish birdie-birdie-birdie was nice."
Malayasia's Green, the Asian Tour Order of Merit champion in 2017, was in the first group out and made full use of the calmer morning conditions as he stormed to six-under through the first 10 holes.
He then made two three-putt bogeys on the 12th and 14th holes, but picked up shots on the picturesque 16th and 17th holes for his 64.
He was denied sole possession of the lead when his birdie attempt on the par-5 18th horse-shoed out from six feet.
"I played solid. A couple of pretty big par saves, and a couple of three-putts, which was tough to take in because I was playing so well," said Green, who is yet to win on the European Tour.
Five-time major champion Phil Mickelson had a storming finish as he came back in 29 shots to be tied with five others at four-under.
Mickelson looked out of sorts going out but stormed down the back nine despite hitting a shot into the water on the 13th, which led to a bogey. He made seven birdies and a solitary par on the 17th hole.
"It was a great back nine ... things really started to come together. I hit a lot of good shots, I started making the putts, and made a lot of birdies, and that gave me a good chance heading into tomorrow," said Mickelson, who turns 50 this June and has dropped to 86th in the world rankings.
"I feel like my game is a lot sharper than I've been scoring, so it was nice having that back nine."
World number one Brooks Koepka struggled on the back nine and finished on even-par 70, while defending champion Dustin Johnson, playing in the morning session, started solidly for a three-under par 67.
Australia's Lucas Herbert, winner last week of the Dubai Desert Classic, carried his form to Saudi Arabia and is level with Johnson and five others.
First-round scores from the Saudi International at the par-70 Royal Greens Golf Club course:
64 - Gavin Green (MAL), Graeme McDowell (NIR)
65 - Henrik Stenson (SWE), Sebastian Soderberg (SWE), Adri Arnaus (ESP), Victor Perez (FRA), Jhonattan Vegas (VEN)
66 - Phil Mickelson (USA), Tom Lewis (ENG), Andy Sullivan (ENG), Ross Fisher (ENG), Aaron Rai (ENG), Ryan Fox (NZL)
67 - Dustin Johnson (USA), Sebastian Garcia Rodriguez (ESP), Lucas Herbert (AUS), Francesco Laporta (ITA), Joost Luiten (NED), Soren Kjeldsen (DEN), Marcus Kinhult (SWE)
68 - Alexander Bjork (SWE), Matthieu Pavon (FRA), Adrian Meronk (POL), David Howell (ENG), Christiaan Bezuidenhout (RSA), Fabrizio Zanotti (PAR), Sean Crocker (USA), Scott Hend (AUS), Justin Harding (RSA), Jazz Janewattananond (THA), Shubhankar Sharma (IND), Renato Paratore (ITA)
69 - Victor Dubuisson (FRA), Alexander Levy (FRA), Matthias Schwab (BEL), Abraham Ancer (MEX), Pablo Larrazabal (ESP), Jeff Winther (DEN), Richard Bland (ENG), Connor Syme (SCO), Sergio Garcia (ESP), Rafael Cabrera-Bello (ESP), Shane Lowry (IRL), Richard McEvoy (ENG), James Morrison (ENG), Nicolas Colsaerts (BEL)
70 - Chris Paisley (ENG), Raphael Jacquelin (FRA), Rasmus Hojgaard (DEN), Maximillian Kieffer (GER), Guido Migliozzi (ITA), Thomas Pieters (BEL), Matt Wallace (ENG), Sam Horsfield (ENG), Stephen Gallacher (SCO), Lee Westwood (ENG), Jack Singh Brar (ENG), Li Haotong (PRC), Richie Ramsay (SCO), Brooks Koepka (USA), Maverick Antcliff (AUS), Sebastian Heisele (GER)
71 - Dean Burmester (RSA), Robert Rock (ENG)
72 - Ernie Els (RSA), Ian Poulter (ENG), Robert MacIntyre (SCO), Akshay Bhatia (USA)
73 - Thomas Detry (BEL), Thomas Bjorn (DEN), Martin Kaymer (GER), Patrick Reed (USA)
74 - Mike Lorenzo Vera (FRA)
75 - Bernd Wiesberger (AUT)