• Photo Gallery: U.S. Senior Open, Round 1

  • Fans watched as Colin Montgomerie teed off on the 10th hole during the first round of the U.S. Senior Open on Thursday. Montgomerie finished at 6-under for the clubhouse lead. (Scott Halleran/Getty Images)Fans watched as Colin Montgomerie teed off on the 10th hole during the first round of the U.S. Senior Open on Thursday. Montgomerie finished at 6-under for the clubhouse lead. (Scott Halleran/Getty Images)