Town took an early lead through a Lewis Travis own goal, before Rhian Brewster levelled from the spot.
But Town took all three points after sub Kasey McAteer picked out Leif Davis for the headed winner with just over ten minutes left.
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And Eustace said it was Town’s depth which won the game – the Blues bringing on McAteer, Dan Neil, George Hirst and Chuba Akpom in the second half.
“I thought it was a great game,” he enthused. “It was two good teams, going toe-to-toe, and it was really exciting to watch.
“I was very proud of the efforts of the group. You can see how we’re building and growing.
“I thought to come up against probably the best team in the league with the best squad of players to go toe-to-toe with them was really pleasing.
“We got a deserved equaliser and felt we could maybe go on and win the game. They’ve made a lot of positive changes then as well.
“You look at their bench and that’s obviously why they’re the top team. They’ve got the best squad.
“It certainly made a difference, but the way we kept going was really pleasing.”
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Former Town loanee Lewis Travis scored an own goal and was sent off (Image: Ross Halls)
It was a bad day for ex-Town loanee Travis, who scored the own goal and was then sent off late on after being shown a second yellow card for a scuffle which left Darnell Furlong on the deck.
Of the sending off, Eustace opined: “Obviously I felt there was a very early booking right at the start of the game, which kind of set the tone for how the referee wanted to do things, which is fine.
“Everyone’s then on tenterhooks really. I think you’ve got to realise the scale of the game and that’s what it’s all about.
“I am disappointed that he’s been shown that second yellow, and when I watch it back, if he has deliberately fell on the lad, then he’ll get punished.”