CORK, Ireland — Lance Armstrong pulled out of the Tour of Ireland in heavy rain during the final stage today.

Russell Downing of Britain won the race after Norway's Lars Petter Nordhaug captured the final stage.

Armstrong abandoned the race during the finishing circuit in heavy rain that also forced organizers to cancel the final lap. The field had reached the finishing circuit in Cork when the seven-time Tour de France winner withdrew. He had finished 20th overall Saturday in the three-day race, 26 seconds behind Downing.

"About to fly to Dublin," Armstrong said on his Twitter page. "Rough day today on the bike. The ol' back was not in a good way and st patty's hill (St. Patrick's Hill) wasn't looking too cozy."

Armstrong finished third in this year's Tour de France after coming out of retirement.

Downing and Nordhaug broke away from a chasing group Sunday, but Nordhaug crossed the finish line ahead of the British rider, who won the first stage Friday.