Lowry had only hit one eagle in his Open career before, at Muirfield in 2013, but was frustrated with his inability to capitalize on the momentum after tripling that particular tally.
His double had seen him run to -9 and left him in contention to join those charging in the afternoon, but three bogeys nearly brought him back to where he started before boarding the train to the Eagle.
The 35-year-old birdied the last to sign for a 69 but he couldn’t hide his disappointment with how the rest of his innings went.
“It was a very emotional day,” he said. “I felt like in the middle of the front nine, I was fine, I wasn’t doing anything good.
“Obviously 9 and 10 happened and I felt like I was in the tournament. And I did well to play my way out of the tournament from there.
“Pretty bored, to be honest. I keep telling myself that you want to end up in the back nine on a Saturday with an opportunity to do something big.
“I found myself there today and I didn’t perform. Einstein wouldn’t have to figure out what was wrong with the back nine. My putting was horrible.
“I shot 1 under for the last seven holes and I’m very optimistic about my chances for tomorrow. Now I have no chance. It’s just very disappointing.