The Premier League giants were beaten at home by rivals Chelsea on Sunday.
Despite being 2-0 up, Spurs went down 4-3 having let in four unanswered goals.
Post-game, Postecoglou said: “Yeah. Obviously it's a painful one because we started the game really well. Not just the goals we scored but the way we were playing. We were really in control of the game and had some really good opportunities apart from the two goals. Then you lose Cristian after the second goal which is just the way our season has gone.
“Nothing has run smoothly and they capitalised before we had settled back down to score. I still felt that in the first half we had the better moments to get a third goal, a couple of key ones.
“In the second half they came out and put us under pressure. I felt we were handling it not too badly and then when they scored we had a big moment at 2-2 to go 3-2 up and in these kind of games, those moments are important. We don't take it and then both penalties were poor on our behalf. They're self-inflicted and unnecessary challenges. We've given them two goals away for no reason and given ourselves a mountain to climb which proved too hard.”
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