McIlroy carded seven birdies and two bogeys in an opening 65.
Four consecutive birdies on the back-nine gave Rory McIlroy Thursday's round of the day at the US PGA Championship.
Everton beat Crystal Palace 3-2 to confirm their Premier League status for another season, but there were unsavoury scenes afterwards.
The Toffees will play in the top flight for a 69th consecutive campaign.