`` # 1 again without touching a golf club this week ... . Luke Donald needed a top- 1 finish at the RBC Heritage to keep No . 1 ranking . Zach Johnson and Rory McIlroy have switched places three times already this season . Sweden 's Carl Pettersson won the tournament by 1 shots from Donald .
Luke Donald needed a top- 1 finish at the RBC Heritage to keep No . 1 ranking . Zach Johnson and Rory McIlroy have switched places three times already this season . Sweden 's Carl Pettersson won the tournament by 1 shots from Donald .