England's Simon Dyson shot an opening round 5-under 65 Thursday to tie for the lead with Marcel Siem on a day marred by vandals and torrential rainfall.

Play was delayed for 45 minutes after vandals dug up parts of four greens at the Hilversum Club. Heavy rain later soaked the course, forcing players off for more than three hours.

Despite the delays, Dyson had an eagle at the 484-yard, par-5 12th and finished with five birdies and two bogeys. He won the event in 2006 and 2009 on the Kennemer course. Germany's Siem also had an eagle on the 12th and finished with four birdies and a bogey in his 65.

Defending champion Martin Kaymer struggled to 3 over after 15 holes before the rain delay. He added another bogey after returning to play and shot a 74.

Lee Westwood, who won the tournament in 1999, had back-to-back bogeys on holes 5 and 6. He had birdies on the next two holes before play was called off because of darkness with 78 players not completing their first round.

U.S. Open champion Rory McIlroy got off to a slow start, with a bogey 5 on No. 3. He was one over after eight holes before play ended.