Rory McIlroy and Graeme McDowell both slipped out of contention on the final day as Scottie Scheffler won the Arnold Palmer Invitational by one stroke.

PGA Tour rookie of the year in 2020 Scheffler (25) finally broke through last month to win the first tournament of his career, the Waste Management Phoenix Open, and repeated the trick with an even-par 72 closing round to finish at five-under at Bay Hill in Orlando, Florida.

England's Tyrell Hatton, Viktor Hovland of Norway and overnight joint leader Billy Horschel were all one shot further back.

McIlroy and McDowell had both started the day in joint sixth, four off the lead, but finished in a tie for 13th on one over after both shooting 76.

McIlroy's challenge was done early after a double bogey on seven and he snapped his wedge after an overhit pitch on the 12th.

McDowell was one over thru 15 but then slipped out of the top 10 after a double bogey on 16 and another dropped shot on the last.

However, the 13th-placed finish is the Antrim man's best since winning the Saudi International in 2020.

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"I mean I did not swing the club well today off the tee," Scheffler said afterwards.

"I was hitting into a lot of bad spots, but I just kept grinding. I made some key putts there toward the end and then two great lag puts to finish off the round."

The victory moved Scheffler into the top spot of the FedEx Cup standings.

"It means a lot," Scheffler said. "I've been playing some good golf the past few years and it's nice to get a few wins under my belt. I'm looking forward to the rest of the season."