Richarlison was introduced ten minutes before full time, with Spurs trailing 1-0 and the Brazilian inspired a turnaround with a goal and an assist to secure a vital victory.
Earlier this week, Richarlison spoke about off-field issues that have affected his performances since making a £60m switch from Everton to North London last summer.
In fact, Saturday's goal against the Blades was only Richarlison's second for Spurs in 32 Premier League appearances.
But Postecoglou is hoping the floodgates will now open for Richarlison to get his Spurs career back on track.
"Yeah Richy was great. I thought all the subs who came on really helped. But that's been a consistent theme," football.london quotes Postecoglou as saying in his post-game press conference.
"And yeah for Richy I think it's the point I was trying to make yesterday - for him to understand that you try and maintain a balance in life. And his football hasn't been that bad, he's still been contributing for us.
"Sometimes when you struggle with certain parts of your life you let it go into other areas. But the football is one area where he can control, and he works hard everyday in training and really got his rewards today.
"And hopefully that gives him a bit more of a settled feel to deal with the other areas in his life. For everyone, it's about not letting it overwhelm you. And hopefully a day like today helps him."
Tottenham's unbeaten start to the season will be put to the test against Arsenal in the North London derby next weekend.
