Keane has bemoaned Tottenham's "criminal" defending after they were beaten 2-1 in their opening Champions League group game against Monaco.
Speaking on ITV's highlights programme on Wednesday night, former Manchester United midfielder Keane said: "I think it was a tough night for Tottenham.
"That's one of the problem with Spurs, you never know what you're going to get. Brilliant at the weekend and then tonight, when it was set up with a huge crowd, the two goals they gave away in the first half an hour, it's criminal, it really is.
"The manager will be fuming with the defensive side of the team tonight. To give those goals away at that level, there's no coming back."