SANDWICH, England  — Another major goes to Northern Ireland. The surprise was Darren Clarke’s name on the claret jug.

Ten years after he last contended in a major, no longer in the top 100 in the world, Clarke delivered his defining moment Sunday in the British Open when he held off brief challenges from Phil Mickelson and Dustin Johnson to win golf’s oldest championship.

The weather was so wild that heavy rain changed to sunshine, back and forth all afternoon, while the wind was relentless.

Clarke was a steady presence through it all.

A 20-foot eagle putt on the seventh hole gave him the lead for good, and he didn’t drop a shot until it no longer mattered. With bogeys on the last two holes, Clarke closed with an even-par 70 for a three-shot victory over the two Americans.

“Pretty amazing right now,” Clarke said, the claret jug at his side. “It’s been a dream since I’ve been a kid to win the Open, like any kid’s dream is, and I’m able to do it, which just feels incredible.”