Rovers - who had been setting the pace up until their recent wobble - were 1-0 down at the interval thanks to Brad Inman's strike.
However as the home side turned the screw after the break, McGurk and Power both found the net to secure the three points.
Despite Tranmere dominating possession early on it was the visitors who took the lead after 12 minutes - Newcastle loanee Inman reacting first to fire home his third goal in as many league games.
The Alex thought it was two-nil minutes later but an Inman effort was ruled out after Lauri Dalla Valle fouled Zoumana Bakayogo in the build-up.
Tranmere got themselves level in the 58th minute - McGurk leaping highest in the six-yard box to power home a fine header.
Liam Palmer's bobbling effort then hit a post as Rovers pressed for a winner and soon after 19-year-old Power provided it - curling into the top corner from the edge of the box.
