“Overall I played a really good round of golf, exactly what I needed to do,” McIlroy told PGA Tour Radio.
“I think hitting it on the fairway is key. If you hit it on the fairway at least you can get some spin on your ball and get it somewhat close to these holes.
“It’s firm, it’s fast and there’s a little bit of wind and they have tucked the pins away so it’s tough to get close.
“It’s sort of like a game of chess out there. You have to stay patient and pick your spots.”
Overall, McIlroy said he was pleased with his play in the new season.
“I’ve been trending in the right direction,” he said. “I am coming off four top-fives to start the year.”
Australian Aaron Baddeley (69), Englishman Matt Wallace (69) and American Kevin Kisner (70) shared third at seven-under.
Third round co-leaders Tommy Fleetwood (76) and Keegan Bradley (75) stumbled out of contention after beginning the day with a four-stroke advantage.
The troubles also continued for world number two Justin Rose, whose 77 left him 12 strokes off the lead.
Watch the final round of the Arnold Palmer Invitational on Sky Sports Golf