Scottie Scheffler claimed a share of the first-round lead at the US PGA Championship as Rory McIlroy finished a difficult first day seven shots back. Scheffler was one of the last groups out at Aronimink Golf Club in south-west Philadelphia , on a day where low scoring had proved elusive. He ended it three under, part of a seven-way group at the top of a congested leaderboard which featured German Martin Kaymer , 12 years on from the last of his two major wins. A record 33 players are within two shots of the lead, eclipsing the previous high of 28 at the 1993 Open, including 12 major champions. Scheffler started steadily but dropped a shot at the fifth. He made his move with back-to-back birdies at six and seven before salvaging par after chipping out of the greenside bunker at the monster 245-yard par-three eighth. A third birdie came with a 28-foot putt on 10 to move two under and he joined the leading pack with another at 11.…