Shane Lowry moved to within a stroke of leader Kevin Mitchell after he shot 65 to finish the second round of the Truist Championship at 11 under.
The Irishman’s round featured six birdies and was the lowest of the day in soggy conditions on Philadelphia Cricket Club’s Wissahickon Course.
Overnight leader, American Mitchell, who led the way with a 61 on Thursday, made two bogeys and five birdies in his round of 67.
“There’s a consistency to my whole game that has been very good,” said Lowry.
“I think I’m just maturing as a golfer, taking the rough with the smooth, the good days taking them well and the bad days working through them.”
The 38-year-old dismissed suggestions the damp conditions in Pennsylvania played to his strengths.
“Everyone says that to me every day when it rains!” added Lowry.
“I live in South Florida. I think I’m able to handle them probably better than a few people, but I don’t particularly like or enjoy going out and playing in these conditions.”
Rory McIlroy – last year’s winner and a four-time champion at the event – had an up-and-down round which included six birdies and three bogeys.
The 36-year-old Northern Irishman, who completed a career Grand Slam with his thrilling win over Justin Rose at last month’s Masters, ended the day in a six-way tie for fourth on seven under.
“I felt like today was another sort of scrappy one,” said McIlroy.
“I made what I feel are some uncharacteristic mistakes compared to how I’ve played the majority of the year.
“So just got to try to iron that out over the next couple of days, try to shoot a couple of scores without as many bogeys on the card.”
Tommy Fleetwood made his second consecutive round of 68 to finish on four under, but fellow Englishman Rose is well off the pace at seven over after a round of 77.