The Scottish striker delivered a first-half piledriver to help Pompey earn a 2-2 draw against fierce-rivals Southampton on Saturday.
Maguire admitted the goal was up there with the best he has scored in his career. And he revealed he knew the magical moment would arrive.
He said: ‘I knew I was due a screamer and I said before the game I’m going to score a cracker.
‘I picked the ball up in my own half, gave it to Kelvin Etuhu and supported him.
‘Thankfully, he gave it to me and I just hit it and it flew into the top corner. It’s up there with the best of my goals.
‘It’s a derby match and the first I’ve really played in. It was a great feeling.
‘It’s a while since I hit one as good as that but I’m a striker and I’m supposed to shoot.’
Maguire was blown away by Pompey’s support and couldn’t resist joining them after David Norris’ late, late leveller.
He said: ‘The fans were brilliant and stuck with us.
‘When the goal goes in late and you look at the crowd you get carried away.
‘The next thing I knew I was in there with them. It shows we are all in this together.’