Tyrrell Hatton birdied his final hole to take a one-shot lead into the final round of the Abu Dhabi HSBC Championship, where Dustin Johnson surged into contention.
Hatton closed a four-under 68 to edge ahead of a congested field at Abu Dhabi GC, where US Open champion Johnson is one of five players one-shot back and three strokes separate the top-16 players.
Johnson birdied three of his opening six holes and chipped in at the eighth to reach the turn in 31, before firing a hat-trick of gains from the 15th to close a blemish-free 64 and post the joint-lowest round of the week.
"I played a little bit better today," Johnson told Sky Sports. "The biggest difference was I drove it better, I hit a lot more fairways today and holed a few putts.
"I'm still yet to birdie a par five but I did make an eagle on eight, chipped one in. It was a really solid round."
Overnight leader Kaymer cancelled out a blemish at the fourth by picking up shots at the fifth and eighth, but lost top spot when he kicked off his second nine with back-to-back bogeys.
Three birdies in a four-hole stretch from the 11th saw Hatton move up the leaderboard and join Johnson on 12 under, before Kaymer rolled in a three at the par-four 13th to make it a three-way tie.
Kiradech Aphibarnrat joined the group after finding birdies either side of a dropped shot at the 15th, with Pablo Larrazabal draining a 30-footer at the penultimate hole to leave five players sharing the lead.
Hatton closed a bogey-free back nine with a final-hole birdie to grab the outright advantage at 13 under, with Aphibarnrat, Larrazabal and Kaymer all unable to match his gain at the last.
The trio share second spot with Johnson and Tommy Fleetwood, who birdied the final hole of the day to complete a two-under 70.
First round leader Henrik Stenson closed a second successive 71 to join Lee Westwood in the group three shots back, with Branden Grace and Callum Shinkwin part of the tie a further stroke adrift.
Defending champion Rickie Fowler is five under with one round to play, while 2013 winner Jamie Donaldson is 10 strokes off the lead on three under.
Watch the final round of the Abu Dhabi Golf Championship live on Sunday from 8am on Sky Sports 4 - your home of golf