Adrian Lam admits he was at a loss to explain Wigan's awful display as they fell a hurdle short of Old Trafford.
They came up way short in going down 28-4 against Salford, who will meet St Helens in next weekend's Grand Final.
The Warriors were flat from the start and after trailing 12-0 at half-time, they failed to improve in the second-half as they carried on where they left off with the 40-10 loss at Saints."I can't put my finger on it," said coach Lam. "They were pretty focussed in the week, everything was in place, but it went from bad to worse.
"I'm pretty upset. I'm shell shocked really.
"I can't believe we delivered that in the first 20 minutes, like we did last week.
"The last four weeks have been the same with the starts and I can't put my finger on it to be honest. Everything we seemed to do went from bad to worse, nothing worked. It just wasn't us."
Lam had steered Wigan to a second-placed finish before the play-offs but successive losses mark a disappointing end to the campaign.
"We'll get better from this," said Lam. "This should put us in a better position moving forward."
George Williams, playing his last game at the DW as a Wigan player before his move to Canberra, said: "Massive credit to Salford, I'm not taking anything away from them.
"It's been a massive rollercoaster season, I had every hope of a fairytale ending, but it's not to be."