Shaun Williams' penalty had given the Dons a half-time lead but super-sub Maguire curled in two exquisite late free-kicks to win it for the Sky Blues after fellow debutant Chris Dagnall had levelled.
Pressley said: "I thought our second-half performance was terrific.
"We played with intensity and energy and our closing game was brilliant. Our passing, counter-attack football was terrific.
"I was so proud of them and I'm so desperate to give these supporters success - I can't tell you how much I want to bring this club back to where it belongs.
"That was quite phenomenal, the atmosphere in this ground was terrific and I think it was a big thank you from my players with that type of second-half performance.
"It was a wonderful debut for all three of them - Dan Seaborne was outstanding, Chris Dagnall got his goal that his work-ethic deserved and they were two quite phenomenal free-kicks from Chris Maguire.
"I knew Chris had wonderful set-piece delivery but I didn't know it was that good - they were two world-class free-kicks.
"I'm so pleased for the kid because he's had a difficult period over the last two or three months."