The manager's team were leading 1-0 against Wolves in after Tanguy Ndombele scored 57 seconds into the game on Sunday evening (27.12.20), but they fell to a late goal from Saiss at 86 minutes to leave them with only a draw.
Speaking after the match, Mourinho told BBC Sport: "Defending deep, that's not the intention.
"They know what I asked them at half time, if they couldn't do better it's because they couldn't do better."
The draw means Spurs failed to capitalise on Liverpool, Leicester and Manchester United all dropping points in the Premier League over the weekend.
Jose admitted he and his players are "frustrated" with failing to put the game to bed, and he insisted his team weren't "dangerous" or "ambitious" enough to seal the win.
He added: "We are frustrated with the result. We had control of the game, but we had 89 minutes to score more goals and we didn't.
"It was not just about not scoring goals, it was also about not being dangerous and not being ambitious. For me, that's the problem."
Meanwhile, Wolves boss Nuno Espirito Santo was pleased with his team's efforts and "happy" with their response after going down early to the Ndombele goal.
He said: "I think we performed really well, I think we played a very good game. The result is the consequence.
"We conceded very early in the game, but the team reacted and we played well, very intense, very aggressive against a very dangerous side, very good, very talented. But we played well. I'm happy."