McIlroy, 29 today, is bidding for a hat-trick at the North Carolina venue, where he won in 2010 and 2015.
His three-under par score was among the best of the early starters, leaving him just one shot off the clubhouse lead shared by Peter Malnati and Tyrrell Hatton.
McIlroy got off to a perfect start with a birdie on his opening hole, the par-five 10th, before birdies at the 12th and 15th. A poor drive on 18 found the water hazard, but he escaped with just a single dropped shot to hit the turn in two-under.
He birdied the second but gave the shot back when he missed an eight-footer for par on the sixth, before finishing with a flourish, chipping to within two feet of the seventh hole and rolling in a short birdie putt before parring his way home.
Out of sorts Shane Lowry had five bogeys in total as he struggled around in three-over par, leaving him in danger of missing the weekend cut.
Meanwhile Paula Grant is in action today in the first big event since being named in this summer’s Curtis Cup team. The Irish Women’s Close champion from Lisburn forms part of a strong line-up for this weekend’s Welsh Open Ladies’ Stroke Play Championship at Aberdovey, Wales.
The 24-year-old will be full of confidence after making the eight-woman Great Britain & Ireland team for June’s Curtis Cup at Quaker Ridge, New York.
And she will be out to prove it was the correct decision to include her.
Grant will be joined by Shannon Burke (Ballinrobe), Georgia Carr (Milltown), Elisa Corcoran (Grange) and Canice Screene (Hermitage).
Reigning champion Gemma Clews (Delamere Forest) will not be defending the title and there are plenty of candidates to take her crown.
Teenage sensation Lily-May Humphreys, 16, will be hoping to add to her recent successes.
The Stoke-by-Nayland star won last month’s Helen Holm Scottish Women’s Open Championship, which followed a number of triumphs in 2017, including the Girls’ British Open Amateur Championship and European Young Masters.
Border Championship winner Shannon McWilliam, 18 and Sophie Lamb, 20, will also be involved.
The trio will team up with Grant in the Curtis Cup.
The field will play 18 holes today and tomorrow before the top 50 and ties advance to Sunday’s final round.
The golfer with the lowest score over the 54 holes will be declared the winner. In the event of a tie the winner will be decided by a sudden-death play-off. Each nation can also name two teams consisting of two or three players for the team trophy. The two lowest scores in each of the three rounds will count towards the team’s total.