DEFENDING champion Rikard Karlberg opened up a one-shot lead as the weather wreaked havoc on day one of the Italian Open at Golf Club Milano.

A total of four hours and 55 minutes was lost to torrential rain and the threat of lightning in Monza, leaving 17 players unable to complete a hole and all of the later starters with at least 10 holes of their first rounds to finish.

Ryder Cup stars Danny Willett, Matthew Fitzpatrick and Martin Kaymer were among those affected as they all birdied the first before the hooter sounded to end the day due to darkness, while Andy Sullivan was level par after three holes.

Karlberg was able to get his first round completed and he did it in some style, rolling in a 20-foot eagle putt on the ninth to add to six birdies and a bogey and get to seven under.

"That's as good as it gets," he said. "It was great round. I felt at a few tournaments there have been too many bogeys, I haven't been able to save par to get the round going and today I did that and in the end we shot seven under. I'm very happy with that."

Local favourite and 2006 champion Francesco Molinari was at six under after a bogey-free 65, a shot clear of Swede Robert Karlsson and Spain's Adrian Otaegui.

English pair Richard Bland and David Horsey, Wales' Rhys Davies and Scot Jamie McLeary were then all in a group of nine players at four under.

Chris Wood fared the best of the Ryder Cup pl