Warren fired a five-under 67 to become the first player in the clubhouse on 13 under, and he was soon joined by Emiliano Grillo before Branden Grace and Bernd Wiesberger both birdied the last to set up an intriguing final 18 holes.
Eddie Pepperell made the most significant move of the day as he birdied the final three holes to cap a scintillating 65 – matching the best round of the week – and set the early target at 11 under.
Justin Rose will be looking to pressure the leaders as he goes into the final round seven off the pace, but defending champion Sergio Garcia plummeted out of contention after coming home in 42 to hand in a 77, the joint-worst score of the day.
Warren cruised to the turn in 33 and started the inward stretch with his fourth birdie, and he responded to a bogey at 14 with immediate back-to-back birdies before parring safely in to secure a place in the last group out on Sunday.
The Scot will play alongside the in-form Grace, who got off to an erratic start as he followed an opening birdie with dropped shots at the third and fourth before he got back on track with birdies at the next two holes.
He picked up further shots at 10 and 13, and he did well to get up and down from the lush, thick rough surrounding the 18th green for a closing four and a four-under 68.
Warren told Sports 4: “It was good, really solid today. I missed a few??greens on the back nine but my short game held it together, with a few good iron??shots coming in. Overall it was a really pleasing day.”
Grillo struggled to get anything to happen as he parred the opening six holes, but the Argentine made huge strides up the leaderboard with four birdies in five holes around the turn and added another birdie at 16 before closing out bogey-free 67.
Wiesberger continued his good form, his only blemish coming after a wayward approach into the desert scrub at the 16th, and a delightful wedge to three feet at the last set up his fifth birdie of the day as he matched Grace’s 68.
But the hottest player of the day was undoubtedly Pepperell, who raced out of the blocks with three birdies in four holes only to stall his momentum with a disappointing bogey-six at the ninth.
He replied with birdies at 10, 11 and 13 around another dropped shot at the 12th, and his sparkling finish swept him into the clubhouse lead as he vaulted 27 places up the leaderboard.
Pepperell was joined at 11 under by Alejandro Canizares and George Coetzee, who both kept bogeys off their cards in rounds of 68 and 70 respectively, while first-round leader Oliver Fisher carded a mixed-bag of a 69 to stay in contention on nine under par.
He said: “I hit the ball well – better than I had the first two days – but I??also putted better. I holed a number of good-length putts – 16, 17 and 18, they??were all putts over 15 feet and nice ones to hole.”
Meanwhile, Rose got off to a shocking start with an ugly double-bogey seven, but he bounced back with four birdies over the front nine and made a superb eagle-two at the driveable 16th to give himself an outside chance of contending on Saturday.
World No 2 Henrik Stenson was again out-of-sorts in a 71 that leaves him at four under, but Garcia slumped 12 shots behind the leaders after a horror show on the inward half.
The Spaniard was two under for the day and eight under for the tournament after 10 error-free holes, but he double-bogeyed the 11th and ran up a seven at the par-four 15th while dropping three further shots.