Maguire headed home a Tom Barkhuizen cross to put North End in front in the 23rd minute but the Tykes levelled within two minutes through Brad Potts.
It was a game which lacked a bit of quality and control, PNE the better side but not able to find a cutting edge up front.
They nearly snatched the three points in stoppage-time, Maguire's shot from a Tommy Spurr long throw-in, tipped over the bar by Barnsley keeper Adam Davies.
Alex Neil had made three changes to the PNE starting XI, Paul Gallagher, Spurr and Stephy Mavididi coming into the side.
Injury kept Ben Pearson and Daniel Johnson sidelined, while Ben Davies made way for Spurr in the centre of defence.
Gallagher - making his 500th club appearance - was partnered by Alan Browne in the centre of midfield, Barkhuizen on the left-wing and Mavididi on the right - Maguire playing off Jordan Hugill.
Maguire created North End's first chance of the contest, getting down the left side of the box and pulling a cross from the byline into the path of Hugill who hit a first-time shot wide of the target.
A Mavididi cross was headed straight at the keeper by Maguire, while a Barkhuizen centre then hit the Irishman on the chest and bounced wide.
Maguire's persistence paid off when he put the home side into the lead in the 23rd minute.
Barkhuizen was the creator, taking the ball past the Barnsley right-back and sending over a left-footed cross which Maguire rose to head past the keeper and inside the far post.
Within two minutes the visitors levelled, Adam Hammill's cross from the right-wing creating confusion in the six-yard box and bundled home by Potts - Darnell Fisher's attempted clearance appearing to hit him.
Five minutes before the interval, Potts fired high over the bar and into the Town End after Spurr's headed clearance had fallen into his path.
At the other end, a Mavididi pass gave Browne a sight of goal, the midfielder's shot from outside the box comfortably gathered by keeper Davies.
Three minutes into the second half it needed a goal line clearance from Fisher to prevent North End falling behind.
Ryan Hodges beat Josh Earl on Barnsley's right, his ball inside finding Potts who shot goalwards.
The midfielder's effort clipped off Ike Ugbo and Chris Maxwell, with Fisher showing a calm head to trap the ball on the line and clear.
North End went close to a second goal in the 54th minute, Gallagher's corner from the right met with a powerful header by skipper Paul Huntington but struck team-mate Mavididi in a crowded six-yard box.
Browne sent a volley from outside the box straight down the keeper's throat after a corner had been cleared by the visitors' defence.
John Welsh and Josh Harrop came off the bench in the 70th minute, replacing Gallagher and Barkhuizen, this Welsh's first involvement in the side since badly tearing a calf muscle last October.
Barnsley substitute George Moncur cut inside from the left channel and fired straight at Maxwell, then within sixty seconds, Harrop sent a shot from 20 yards whistling just over the bar after riding a couple of challenges.
North End exerted some late pressure and nearly snatched it in stoppage-time.
Spurr's long throw-in from the left bounced across the box to Maguire, his shot bouncing into the ground before being tipped over by Davies.
PNE: Maxwell, Fihser, Huntington, Spurr, Earl, Gallagher (Welsh 70), Browne, Barkhuizen (Harrop 70), Maguire, Mavididi (Robinson 78), Hugill. Subs (not used): Vermijl, Horgan, Davies, Hudson.
Barnsley: Davies, McCarthy, Jackson, Lindsay, Pearson, Williams, Gardner (Moncur 66), Potts, Hammill (Bradshaw 81), Hedges (Barnes 71), Ugbo. Subs (not used): Pinnock, Thiam, Bird, Townsend.
Referee: Peter Bankes (Merseyside)
Attendance: 12,813 (1,745 away)