Rikard Karlberg has recorded a first-round 64 to move to the top of the leaderboard at the Italian Open.

The Swedish player won this event 12 months ago and he has given himself the best possible chance of defending the trophy with six birdies and an eagle on a rain-hit day in Monza.

Home favourite Francesco Molinari is one shot adrift in second place, while Robert Karlsson and Adrian Otaegui share third position.

English duo David Horsey and Richard Bland are two of a large group of players who share fifth, but Ryder Cup wildcard Lee Westwood could only end the day on one-under-par.

Masters champion Danny Willett was one of many players who did not get their round underway until the evening after a five-hour delay earlier in the day.