Matthew Fitzpatrick fired a flawless five-under 67 to earn a one-shot lead over in-form defending champion Rory McIlroy ahead of the final round at the Arnold Palmer Invitational.
The 24-year-old seized the narrow advantage as he posted five birdies in an assured display at Bay Hill, after McIlroy propelled himself up the leaderboard earlier with a seven-birdie 66.
Fitzpatrick, a five-time winner on the European Tour, dealt with testing pin positions and windy conditions in Florida to top the standings on a day where English golfers - overnight co-leader Tommy Fleetwood aside - excelled.
Matt Wallace, playing alongside Fitzpatrick, is two shots off the lead after he carded a second successive three-under 69 to sit at seven under alongside Australia's Aaron Baddeley and American Kevin Kisner, with Spain's Rafa Cabrera Bello in a five-strong group one shot further back.
Fitzpatrick started his campaign with a pair of 70s but demonstrated his growing maturity on the sport's biggest stages with an excellent showing on day three, as an opening birdie saw him begin in perfect fashion.
A second gain soon followed at the par-five fourth and after consistent hitting from tee to green saw him turn in 34, he began his back nine with a third birdie of the day to continue his progress up the leaderboard.
Fitzpatrick, who has vastly experienced caddy Billy Foster on the bag this year, sunk a 14-foot birdie putt at the 15th to join McIlroy at eight under before another gain at the next hole saw him hit the front and he held firm under pressure to retain his lead with a pair of closing pars.
McIlroy, who has already enjoyed four top-five finishes this season, is well placed to win for the second year running after a vintage display of ball striking and short game ability around the greens thrilled the watching galleries.
McIlroy: First win of 2019 very close
The four-time major champion's approach play to the greens helped set up a tap-in birdie at the 15th as he finished with three birdies over his closing four holes, after he had begun purposefully with four gains inside the first six holes, before a minor blemish at the eighth.
Wallace relished the opportunity to further impress his game on the US tour as he mixed five birdies with two bogeys in an exciting round to enhance his chances of adding to his four wins on the European Tour.
Cabrera Bello, who led after the first round, mixed six birdies with four bogeys to reach six-under, while Fleetwood, who struggled to a disappointing four-over 76, is joined by compatriot Tyrrell Hatton at five under after his countryman fired a six-under 66.
Watch live coverage of Sunday's final round at the Arnold Palmer Invitational on Sky Sports Golf from 4.30pm.