American golfer J.J. Spaun opened the 2025 U.S. Open at Oakmont Country Club with a bogey-free four-under-par 66 on Thursday, matching the championship’s lowest first-round score at the storied venue and becoming only the eighth player to record a clean card in a U.S. Open at Oakmont. Spaun’s round, featuring four birdies and six up-and-downs after missed greens, gave the 33-year-old a one-shot lead over the field and defied 66-to-1 pre-tournament odds to top the leaderboard after 18 holes. World No. 1 Scottie Scheffler, Rory McIlroy and other major champions were left chasing, while Sam Burns and South Africa’s Thriston Lawrence finished the day at three under. The California native kept himself in contention with a third-round 69 on Saturday to reach three under overall and sit tied for second, two strokes behind the leaders. The statistical quirk underscored Oakmont’s difficulty: none of the previous 12 first-round leaders in U.S. Opens at the course had broken 70 in the second round, averaging 74.4. Sunday’s final round turned into a roller-coaster. After bogeying five of his first six holes and shooting 40 on the front nine to slip four shots back of Sam Burns and Adam Scott, Spaun rallied. He holed a 40-foot birdie putt at the par-3 12th, converted another on 14 and then drove the green at the 313-yard 17th, setting up a decisive birdie. The surge moved him to one over par for the championship and gave him a one-stroke advantage with only the 18th hole remaining. The outcome of the championship remained undecided at press time.