Maguire, just seconds after coming onto the pitch as a substitute, slotted home the only goal of the game 10 minutes from time. It was his first goal since re-joining the club in the summer.
Chances were created at both ends and the game looked to be heading for stalemate as it entered the final quarter.
With 15 minute left Alfreton almost took the lead in spectacular fashion as Hobson fired a stunning half-volley off the post,.
Blyth almost took the lead shortly after as Liddle found O’Donnell in the area, but Spartans’ top-scorer scuffed his shot straight into the arms of Willis.
With 10 minutes left, Maguire replaced Dale as manager Terry Mitchell went for the win, and it proved to be a masterstroke as the Spartans number nine fired Blyth ahead within seconds of being introduced, after the ball broke to him in the box.
Thomson almost doubled the lead shortly after but Willis was equal to it, before Blyth hearts were in mouths as a looping header from Rhead drifted narrowly wide of the post.
After the game boss Mitchell hailed it as an ‘outstanding’ performance from his side.
"As you can imaging, the dressing room is buzzing,” he said. "We’ve had to withstand loads of direct ball, corner, long throw-ins, everything, but the back line with the goalie behind were outstanding and that was backed up by the front lads.”
Of goalscorer Maguire, he added: “He’s been unbelievable with his work ethic since I joined the club, but he hasn’t had loads of chances. I said to him ‘go on, get your goal,’ and he deserves it. I’m absolutely delighted for him.”
And of new signing Patrick Almond he said: “He did really well. He defended well and showed real composure when he had the ball. I’m sure the fans were delighted with him.”
The victory made it four wins out of five for Spartans, who are on the road again on Saturday (January 29) when they travel to face Leamington.