Victor Dubuisson joined Graeme McDowell at the top of a congested leaderboard as the 2020 Saudi International powered by Softbank Investment Advisers was for set for a dramatic finale.
The 2014 Ryder Cup pairing were reunited in the final group at Royal Greens Golf and Country Club, with McDowell entering day four with a one shot lead over his French former mentee.
The Northern Irishman ground his way to a front nine of 36 to slip to 11 under, with Dubuisson joining him as he played his first nine in level par.
McDowell went left off the first tee to surrender an opening bogey and with Dubuisson failing to get up and down from sand on the third, the final group were coming back to the field.
Green had used the contours of the second green beautifully to set up a birdie from six feet, while Mickelson made birdies on the second, third and fourth to sit two back.
Dubuisson made a two putt birdie on the par five fourth to move back into a share but gave the shot straight back after missing the green on the next - where McDowell made an up-and-down for par.
Green had dropped a shot from the sand on the third but once again used the terrain to his advantage on the sixth, making a birdie from four feet to get back to double figures.
Dubuisson played a stunning shot from the rough on the sixth to once again take a share of the lead and McDowell was doing well to stay there as he got up and down to save par.
The overnight leader had been battling for most of his round but hit an excellent tee shot into the par three eighth and a birdie from 18 feet had him alone at the top once more.
He could not produce more heroics on the next, however, finding sand with his second for a bogey.
Johnson had bogeyed the third but hit back with a brilliant chip-in eagle on the next before a birdie from four feet at the ninth moved him to nine under.