Stars impressed early at the 2021 U.S. Open with a stellar leaderboard coming together through the first day of action. Though the first 18 holes started late due to a fog delay and was unable to finish amid darkness, it will be completed first thing Friday as Round 2 begins. Russell Henley is the leader in the clubhouse at 4 under, while Louis Oosthuizen holds the same score with two holes left to play on the front nine entering the day.A few major champions in Brooks Koepka, Hideki Matsuyama and Francesco Molinari sit at 2 under, just two shots back of the leaders. They are joined by U.S. Open favorite Jon Rahm in that spot. Other big names like Rory McIlroy (-1) and Dustin Johnson (E) are firmly in contention as well, though Phil Mickelson — a fan favorite still looking for the career grand slam after capturing the PGA Championship last month — started 4 over and appears to be a long shot now eight shots back of the lead.CBS Sports will update this story with scores and highlights from the U.S. Open below. Check out the live scores at the top of this story, a more detailed leaderboard, Round 2 tee times and our complete viewer’s guide.