Recalled after a club suspension for a laughing gas episode, Bissouma scored in the 4-0 win.
Postecoglou later said: "Yeah, Biss was good and we know Biss is a good footballer. It's about him being the best version of himself and he will only get there if, as we've spoken a few times, discipline is a big thing for him and I thought it was a disciplined performance for him today you know.
"Not just the goal he scored, but he had a really important job for us. He knew they'd sort of play fairly direct and he had to be there to mop up second balls and intercept things and he was clean for the most part in possession. So good performance.
"No, I'm not surprised because like I said, there's no doubt in his ability, you know. He has that ability to do something special. But, you know, he needs to make sure that he does everything, as I said, he tries and endeavours to do everything right on and off the field to give him the platform to show who he could be as a footballer.
"We certainly believe in him, we’re certainly giving him an opportunity. But as I said before the game, that's just not a never-ending thread, at some point you need to cut it. And it's really up to him to keep going on."