South African Charl Schwartzel has a one-stroke lead after the opening round of the Memorial Tournament in Ohio, while Aussie Matt Jones is right in the mix. The South African, Masters champion in 2011, shot a 65 on Thursday at the Muirfield Village Golf Course in Dublin to sit on seven under, one ahead of American Scott Piercy. Schwartzel made an indifferent start to his round, three-putting his fourth hole of the day from just seven feet for a bogey, but reeled of four birdies in succession after that to reach the turn in 32. He looked on track for a sizzling round with four consecutive birdies on the back nine as well, but let himself down with a double bogey at the par-three eighth, his second-last hole of the day. The 28-year-old regrouped with a birdie at the last for a 65 and a one-stroke lead. New South Welshman Jones, meanwhile, is on three under in a tie for ninth place after shooting a 69. Piercy&aposs 66 has him in outright second on six under, and he is trailed by a chasing pack of four men on five under – Americans Josh Teater, Russell Henley and Kyle Stanley, plus South Korean Charlie Wi. Americans Bill Haas and Matt Kuchar are on four under. After Jones, John Senden is the next best of the Australian contingent on one under, Jason Day is even and Adam Scott is one over the card. Marc Leishman, Robert Allenby and Aaron Baddeley are all on two over. Defending champion Tiger Woods made a 71 with five birdies and four bogeys to sit on one under, while Rory McIlroy endured a terrible round of 78 to sit on six over the card. McIlroy birdied his first hole, but after four-putting his third hole of the day for double bogey, the Northern Irishman unravelled, with another six bogeys to be at the foot of the leaderboard.