Rookie William Mouw captured his first PGA Tour victory on Sunday, firing a bogey-free nine-under 61 to win the ISCO Championship at Hurstbourne Country Club in Louisville, Kentucky. The 24-year-old Californian finished at 10-under-par 270, overturning a seven-stroke deficit that stood as the Tour’s largest final-round comeback since Jon Rahm’s win at the 2023 Sentry Tournament of Champions and the biggest in the event’s history. Mouw’s closing 61 matched the tournament’s low round of the week and marked the lowest finish by a Tour winner since Ludvig Åberg posted the same number at the 2023 RSM Classic. He claimed the USD 720,000 first prize, a two-year Tour exemption and a berth in next year’s PGA Championship, securing the rewards in only his 20th PGA Tour start. Third-round leader Paul Peterson shot a 69 to finish one stroke back at nine-under 271. Manuel Elvira took solo third at seven under after a 66, while Kentucky native Vince Whaley and England’s David Skinns shared fourth at six under. Mouw birdied seven holes in the first 13 and never dropped a shot, then waited nearly two hours before Peterson’s missed 55-foot birdie attempt on the 18th confirmed the breakthrough win.