Manager Stuart McCall conceded Motherwell were "rotten" in their at Fir Park.
But he is sure last year's Premiership runners-up can recover from a sluggish start to the season.
"We were really poor in all departments," said McCall. "I don't think we mustered an attempt at goal.
"I'd be concerned if it carries on but we'll work hard to put it right. You don't become bad players overnight."
Motherwell have scored just one goal in their opening three matches and striker John Sutton was an isolated figure as Inverness dominated possession for long spells.
"Basic stuff we couldn't do," sighed McCall. "We couldn't pass from A to B.
"I'm pleased we don't have a game next week because we've got a lot of hard work to do.
"Inverness were very good and deserved it, massively. Their passing and moving really showed us up. We under performed.
"We've not been up at it; certainly when it comes to creating chances. We had big John Sutton up there and he had nothing to feed on. He's not had anything from wide areas.
"The teams we've had at Motherwell have always scored goals but we are struggling, we're not creating.
"I said at half time it can only get better because we were woeful. Second half I don't think we were much better, if I'm honest.
"That's probably one of our poorest performances; certainly here."
Motherwell won their opening match of the season at home to St Mirren but went down 1-0 to Dundee United in midweek ahead of the dispiriting loss to Inverness.
However, McCall was adamant in his post-match media conference that the team would rediscover the form of last season.
He said: "I'm the manager and I take responsibility for that and we need to make sure we improve.
"With the character of the players, I'm confident we will but we need to do it quickly.
"There are a lot of individuals nowhere near the level they were at last season.
"In the seasons past it's been pretty easy to pick my starting XI because of the consistency of the side but I'd be struggling just now to name a team for next time.
"But that doesn't mean we can't turn it round. We just need to work hard and put a lot of organisation in.
"We have to learn from today and bounce back. We've got to be better."