McIlroy had a pair of eagles on his card, including a 2 on the par-4 seventh hole, and the effort left him in a tie for eighth, six shots behind leader Thomas Bjorn.
"It was a good day. I played well, and hit a lot of solid shots," McIlroy told reporters. "The two eagles helped, obviously, and it's one of my better rounds at this place."
The Ulsterman made headlines Wednesday when he announced that he and former fiancee Caroline Wozniacki had called it quits. The pair got engaged on New Year's Eve, but after sending out wedding invitations this past weekend McIlroy explained that he realized he "wasn't ready for all that marriage entails."
McIlroy said during a pre-tournament interview that he is hoping to pour his energy into on-course results this week, a sentiment he reiterated to the media after the opening round.
"I haven't turned on my phone for a few days and I've given my laptop away. I'm sort of living like I'm in the 1970s," he said. "It's a tough week and I'm not really that comfortable standing here talking about it."
McIlroy's track record at Wentworth is hardly stellar, with only one top-10 finish and three missed cuts in six prior appearances. He missed the cut each of the last two years, shooting rounds of 74, 75, 74 and 79 across that span.
His fortunes turned Thursday, though, as McIlroy made two birdies and an eagle on holes 4-7 en route to an outward 33. He added another eagle on the par-5 12th and after a birdie on the home hole, McIlroy completed his second-lowest career score at Wentworth, behind a 65 during the third round in 2009.
"It's a course I've notoriously struggled on in the past, so it was good to shoot something in the 60s," he said. "I'm looking forward to getting back out onto the course tomorrow and hopefully doing that again."
McIlroy was not the only big name to get off to a strong start in England. Players champ Martin Kaymer, FedEx Cup winner Henrik Stenson and Masters runner-up Jonas Blixt all opened with 68, while Bjorn's 10-under 62 tied a course record and gave him a two-shot advantage over Shane Lowry.