The British Open at Royal Troon saw a challenging first round with Justin Thomas leading after a three-under-par 68, while top players like Bryson DeChambeau and Rory McIlroy struggled in the wind and rain, scoring 76 and 78 respectively. Thomas overcame mid-round difficulties to set the clubhouse lead. Other notable performances included Justin Rose playing bogey-free for a 69 and several players finishing strong despite the tough conditions. The tournament highlighted the unpredictable nature of the course and weather, testing even the most experienced golfers.