World No . 1 Rory McIlroy toils on the opening day of the BMW PGA Championship . Lee Westwood , who was beaten by Donald in a playoff at last year 's tournament , birdied the last to finish two-under . Northern Irishman hurls club at four stage as he cards a round of 1 -over-par . Peter Lawrie can usurp McIlroy 's top ranking this week and he sits on one -under . David Drysdale and David Drysdale lead after the first day on six -under .
World No . 1 Rory McIlroy toils on the opening day of the BMW PGA Championship . Northern Irishman hurls club at four stage as he cards a round of 1 -over-par . Peter Lawrie can usurp McIlroy 's top ranking this week and he sits on one -under . David Drysdale and David Drysdale lead after the first day on six -under .