Rory McIlroy made a fast start at the World Tour Championship as he shot a first-round 65 to take a two-shot lead in Dubai.
The world No. 8 went three-under through his first two holes after he eagled the par-5 second, before carding seven-under for his opening round.
Morikawa, who came into the European Tour’s season-ending event as the leader of the Race to Dubai, looked set to join those in a tie for second-place but dropped a late shot at the par-3 17th.
McIlroy is a two-time winner of the World Tour Championship and is back on form after he followed his disappointing performance at the Ryder Cup in September with a victory on the PGA Tour at the CJ Cup last month.
“I think I’ve got a lot of experience around this place, a lot of great memories. It’s comfortable for me,” McIlroy said.
“After the Ryder Cup I put my head down and figured out what I had to get back to. Getting into contention at only one major this year isn’t good enough, but I feel like I’ve got my golf game back.
“I’m excited for those four events next year and for the week ahead because I feel I’m on the right path again.”
Morikawa said: “It was pretty solid throughout. Obviously the two bogeys were a little unforced, but I made a few birdies out there and kept the momentum going and it was a good way to start the first rounds out here.
“I felt really good coming into the week with my irons. They showed up today on a few shots and I hit a couple good 7-irons today and just need to keep doing that. That’s my game. And when putts start to drop, we’re close to [top of] the leaderboard.”