After two chilly days at Aronimink Golf Club, Saturday gave way to bright sunshine, and McIlroy took advantage with a scorching four-under-par 66 to continue his stirring fightback.

A four-over-74 start had left the back-to-back Masters champion in a tie for 105th after the opening round.

But McIlroy declared himself "right back in it" after climbing to a share of 30th at one over on Friday.

Then, after starting his third round five shots back of Americans Maverick McNealy and Alex Smalley, McIlroy reeled in the halfway co-leaders with six birdies in his first 13 holes.

Bidding to become the first player since Jordan Spieth in 2015 to win the season's first two majors, the Northern Irishman had to drain a clutch 12-foot putt to keep the lead on the beastly 551-yard 15th hole, the longest par-4 in major championship history.

McIlroy then dropped a shot with a sloppy bogey on the par-3 17th but still led when he signed his birdie-laden scorecard as the wind began to whip up for the late starters.

Two-time major winner and 2024 PGA champ Xander Schauffele was also safely in the clubhouse at three under after matching McIlroy's Saturday 66.

The two superstars had a swathe of pursuers behind them.

Multiple major winners Jon Rahm and Justin Thomas were sharing the lead on the course at four under midway through their third rounds.

World No.1 Scottie Scheffler, Swedish sensation Ludvig Aberg and former Masters champion Hideki Matsuyama were all locked at three under as more than 30 players stood within two shots of the lead.

Australians Min Woo Lee and the resurgent Cameron Smith were among them.

Lee dropped a shot early to be two under alongside Smith after the 2022 Open champion snapped a run of six-straight missed cuts at the majors.