OAKMONT, Pennsylvania :Bryson DeChambeau has been a fixture on leaderboards at major championships but had a less-than-ideal start to his U.S. Open title defense at Oakmont Country Club on Thursday where thick rough and slick greens took their toll. DeChambeau found himself hitting out of Oakmont's ankle-high rough too often and struggled to find his groove on the speedy greens en route to a three-over-par 73 that left him seven shots back of leader J.J. Spaun and with plenty of work to do. "