Stoppage-time goals from Pablo Sarabia and Mario Lemina completed a late, late comeback against Spurs, who were without injured pair James Maddison and Micky van de Ven and the suspended Cristian Romero and Destiny Udogie.
Eric Dier, Ben Davies, Emerson Royal and Pierre-Emile Hojbjerg came into the side in rare starts at Molineux, while Spurs finished the game with Giovani Lo Celso and Bryan Gil on the pitch, as Postecoglou was forced to use his fringe players.
They led through Brennan Johnson's third-minute goal but were second-best for long periods and struggled to get a foothold in the game.
"We started well but we could have been a bit more positive and be a little bit more aggressive with the ball," Postecoglou said. "I've got to temper that with the fact that we've made so many changes and we're not going to get the same type of fluency, especially when particularly three of your back four are virtually starting for the first time.
"We've made a couple of changes as well further up and it's not going to be as fluent but I just felt we could have been more positive, especially in the first half.
"Second half I thought it wasn't too bad but I just thought and maybe because we were winning the game, I think a lot of the guys in the back of their minds, they haven't played in a while and there was a little bit of self-preservation there to get us through to the end of the game.
"It's all understandable stuff because of the line-up we had out there."
Despite the result, Postecoglou said there were plenty of positives for Spurs and singled out his squad players for praise.
"The character and the commitment, I don't dismiss that," the Australian said. "There's a massive effort to go out against a strong opponent here at home. The guys are playing their first games of the year, you're changing three out of a back four so it's fairly disruptive, especially when guys haven't played at all.
"There's a lot of positives to take from it, they'll be better for the experience, they'll be stronger, so plenty of positives.
"Both of [Dier and Davies] and Emerson, and even for guys like Brennan and Pierre, who haven't started many games because we've had a pretty settled line-up, particularly those two guys coming in, I thought their commitment, their endeavour to play our way was there the whole game.
"You could see they were feeling it towards the end but they didn't let their performance levels drop. For the most part, Wolves didn't have many big chances, I think Vic had one or two saves to make but obviously at the end there.
"I think the first goal was a really good goal and we probably ran out of steam in the last few minutes. Wolves, with the crowd behind them were able to lift."