Huddersfield coach Rick Stone admitted their second half performance was a train crash as they were thumped 38-12 at Hull FC.
The Giants led 12-10 at half time, thanks to tries from Ukuma Ta’ai and Ryan Hinchcliffe, but succumbed to 28 unanswered points in the second half.
Stone said: “I was disappointed we conceded right on half-time. We worked hard for our two tries and gave one up before half time.
“After that, we handed Hull too many opportunities with errors, kicking out on the full, and camped ourselves in our own half.
“We panicked really, it was a bit of a train crash after that because the way we competed in the first half wasn’t reflective of the second half scoreline, that’s for sure. That’s what happens in Super League.
“It’s a harsh lesson, and all the boys realise that. I know they’re better than that and I know they’re disappointed at the scoreboard and the way it ended up.
“We’ve got a bit of work to do.”
Huddersfield are back in action next Thursday when they host Warrington, who also lost on Super League’s opening night, going down 16-12 to champions Leeds.