Asked if Celtic had blown their chance of wresting the title back from Ibrox, the Irishman retorted: "No, no.
"We are very disappointed, there's no doubting that.
"It's over by any means, but it is a big challenge.
"We are 10 points behind and it's no secret that we have to win games but it's not over."
O'Dea insists the Hoops' dressing room is still firmly behind manager Tony Mowbray.
He said: "Oh yes, that's not even a question.
"The manager has got ideas and all the players are completely behind him.
"There is no doubting the effort but effort but isn't enough at a club like Celtic and at the moment we are just lacking a little bit."