Postecoglou's bold decision to field a team of fringe players raised eyebrows, especially after his confident statement about always winning trophies in his second season at clubs. However, in the end, it was his star players who had to step in and save the game.
"There is no easy or quick fix to where we want to get to and one result doesn't change that," Postecoglou told . "We showed what we have been missing the first four games. We have lacked a little bit of an edge and hopefully tonight gives the boys a little bit of belief."
Coventry were superior side throughout and led until two minutes from regulation time after Brandon-Thomas Asante's opener just past the hour. They could have been further ahead but Ben Davies stopped Haji Wright's goalbound shot.
Djed Spence, a half-time introduction who many thought had no future at Spurs before the summer, poked in an equaliser after 88 minutes thanks to his fellow substitute Dejan Kuluseveski's through ball.
TrendingBrennan Johnson then dinked over goalkeeper Ben Wilson, who produced a top save to deny Kulusveski not long before, in stoppage time to seal the win and send Spurs into the next round of the Carabao Cup, breaking Coventry hearts and saving his side's blushes.
' Jamie Redknapp:
"Spurs were so poor and going nowhere fast. Ange will be mightily relieved. But they have to make sure that this is a turning point for them.
"I didn't like the team he picked. I'm a big fan of Ange but l thought he took liberties tonight.
"He didn't select a strong enough team but he has got away with it.
"Tottenham were diabolical up until the goals. Coventry were the better team. Ange Postecoglou will be so relieved.
"Tottenham got away with one, they were very, very fortunate."
Tottenham boss Ange Postecoglou speaking to : "It was a tough game. Credit to Coventry, I thought they were outstanding. They really took it to us. We had to hang in there somehow and we did. In the end credit to the lads. It was a typical cup tie."
On the performance: "We weren't as fluid performance-wise. Some of that is down to Coventry, they played with high energy. In the end I was pleased both for Djed [Spence] and Brennan [Johnson]. They have come on and made the difference for us and made a difference in the game."
On what Brennan Johnson's goal will do for his confidence: "Hopefully a great deal. He's a fantastic young man, a great player. I have a lot of time for him because he works so hard every day. He took his goal well tonight and he made a good impact."
On how significant the result is for Spurs: "There is no easy or quick fix to where we want to get to and one result doesn't change that. We showed what we have been missing the first four games, a little bit of spirit to fight and win. We have lacked a little bit of an edge and hopefully tonight gives the boys a little bit of belief."
Tottenham goalscorer Brennan Johnson speaking to : "It was really difficult. There wasn't one part of us that underestimated Coventry. We have played them a few times and know they play good football. At times we let them off too easy and gave them too many chances. We were under some real pressure but we will always keep going."
On chaos in the game: "That has happened too many times. It has been a bit too chaotic. We gave the ball away too many times, we weren't too much of a threat. For most of the game we didn't play forward enough. The goals came from quick play and that's what we want to do more often."
On his goal: "It was really nice. It's a great feeling to score especially so late. To get in the next round is really important. Penalties is a toss of a coin so getting the goal really late was very beneficial."
Coventry boss Mark Robins speaking to : "For the most part we defended really well when we needed to but also played some good football when we could.
"We worked hard because they worked hard out of possession. I always want us to be brave in possession. We went a bit too long too soon but then settled down into some decent rhythm.
"That's what we have to take out of this game, we have to be more ruthless.
"We deserved something out of that game and we should have gone on and won it."
The Carabao Cup fourth-round draw will take place live on following the conclusion of Liverpool vs West Ham on Wednesday September 25.
Ball numbers for the draw will be finalised on the morning of Wednesday 25 September.
The fourth round ties will take place week commencing October 28.