Adrian Lam described Wigan's performance as the worst this season after their defeat to Catalans at the Nou Camp.
A record Super League crowd of 31,555 watched the Warriors lurch to a 33-16 loss which left Lam bitterly disappointed.
"We didn't get it right, we looked lethargic," said Lam. "We looked like everything we don't want to be.
"I'm very disappointed, I didn't see that coming. It was a great performance last week and we looked flat and tired. Whether that was the Warrington game or the travel taking it out of us, I'm not too sure.
"That was probably the worst we've played all year."
Wigan only trailed 8-6 at half-time but were blown away by a rampant Catalans side which scored three tries in eight minutes to put the game out of sight.
They added a fourth before late consolations from Oliver Gildart and Zak Hardaker.
"If Marshall had got that try early in the second-half, we may have found another gear there, but they went down the other end and scored and we didn't react to it well," he continued.
"We knew they'd turn up and we didn't look interested."
Wigan - eighth in the ladder - wanted the two points to close the gap on the top-five sides.
But the defeat has dialled-up the heat as they switch their attentions to a game at another iconic football venue - their Magic Weekend date with Warrington at Anfield.
Despite the loss, Lam was grateful Wigan had the chance to play in the match at the Nou Camp.
"We want to thank all the fans who came down who made this the Super League record in history," he said. "It was a great chance to showcase our sport to the world.
"It'd be nice to do this again."