Geraint Thomas admitted he went into survival mode after seeing his Tour of Romandy victory hopes ended.
The Cardiff-born rider slipped from third, just four seconds adrift, to 19th overall after Friday’s tough uphill time trial.
Thomas clocked 27 minutes 43 seconds over the 9.9km course from Ollon to Villars – the 27th fastest time and over two minutes off the pace.
“I just didn’t have it,” said Thomas to cyclingnews.com at the finish. “I tried to start with a good pace but just didn’t have it, and I cracked at about halfway.
“Certainly, with 3km to go, it was all about survival. The legs were fading and I couldn’t hold the power and knew from there that I would be just limiting my losses.”
The Team Sky rider is using the race – which has two stages left including Saturday’s mountainous Queen stage – as part of his Tour de France build-up.
Thomas is set to lead the team if Chris Froome is banned over his adverse analytical finding for the asthma drug salbutamol.
He added: “It’s just one of those things but there’s plenty of time until July, that’s for sure.
“Maybe this is the kick that I need.”
Thomas is now two minutes 33 seconds behind Slovenia’s Primoz Roglic.