However, it all looked so different at the start as the home side opened brightly and Sam Hall finished off a flowing movement to put Guernsey in front after 13 minutes.
Northern Ireland replied with a series of attacks and Jamal Dupree missed a glorious opportunity on the half hour when the Guernsey keeper fumbled a cross from Ross Holden but Dupree could only hit the side netting from an acute angle.
Two minutes before the break the visitors drew level with a brilliant goal as Andrew Hoey found the corner of the net with a right foot volley from 25 yards.
On the stroke of half time Ryan Noble-Walker netted from close range after a corner by Hoey rebounded off the bar.
Soon after the restart two goals within a minute for Northern Ireland ended the game as a contest. Hoey added his second goal on 47 minutes following a goalkeeper error and one minute later Dupree shot home from 10 yards.
Northern Ireland was now in complete control and substitute Andrew Mooney drilled the ball in from close range for the fifth goal. Ten minutes later Mooney turned provider as a neat pass created the opening for Adam Salley to complete the scoring.
Northern Ireland will end the tour on Wednesday, hoping to retain the Lynn Nicholson trophy against Jersey in St Helier.
Jason Craughwell, Michael McKenna, Ryan Noble-Walker, Conor McDermott, Ben Doherty (c), Andrew Hoey, Callum Byers,Jamie Dunne, Ross Holden, Ronan Young, Jamal Dupree
Andrew Mooney replaced Dunne 58 mins, Conor Morgan replaced Hoey 58 mins, Adam Salley replaced Dupree 67 mins, Mark Sykes replaced Holden 67 mins, Cameron Stewart replaced McKenna 67 mins, Jamie Rea replaced Young 75 mins.