Latics claim first away win as Josh Sumner grabs injury time winner.
BARNSLEY UNDER 21s 1
WIGAN ATHLETIC UNDER 21s 2
Josh Sumner's 93rd minute strike gave Latics a well deserved away win after taking the lead through Joey Johnson's first goal for the Under 21s, before being dragged level as Brad Abbott scored from the spot for Barnsley.
Latics showed great desire as the game drew to a close and didn't give up to the delight of coaches Graham Barrow and Dennis Lawrence.
Barrow brought in Under 18 regular Johnson to the starting XI for the game at Oakwell Training Complex and also started Danny Redmond and Adam Buxton who have recently been involved with FA Cup match day squads.
It didn't take Latics long to put their authority on the game, with Johnson chasing every ball and Redmond dictate the tempo from the middle.
The 21-year-old was the first to come close for Latics when he curled a free kick left footed from the right wing into the box.
Barnsley's trialist keeper and back four stood still as the ball looked destined for the corner of the goal but, late reactions from the keeper were enough to tip the ball over the bar.
Latics forced another two half chances in the opening half an hour, with Ryan Watson and Johnson both having shots blocked from close range in the area.
The hosts' first chance came as Danny Redmond lay on the ground with a nasty injury as he was caught with studs on the knee but, the referee let play go on and Barnsley powered forwards.
Rhys Oates carried on the attack and sent a long range, curling shot towards Marko Marosi who leaped acrobatically to save.
The ball was still loose though, and was again worked out to the edge of the area this time for Jordan Clark to try his luck but that luck wasn't there as his shot bounced off the bottom of the post.
Play was finally stopped as Redmond was still on the ground, he couldn't continue and was replaced by Rakish Bingham.
Latics started the second half with another chance from a free kick as Ryan Watson delivered the ball into the box from 40 yards, almost catching the keeper out as he couldn't hold onto the ball but Barnsley lived to breathe again as Josh Langley couldn't connect at the back post.
A second substitution was made on 62 minutes as Jesjua Angoy replaced Jack Phillips and two minutes later Latics were into the lead.
Crosses caused Barnsley headaches all afternoon and when another was played into the box and a scramble ensued, it was Joey Johnson who reacted quickest to poke the ball home through a crowd of players in the six yard box.
Barnsley upped their game after conceded and bit back on 70 minutes when Rhys Oates twisted and turned down the right of the area and was taken down by Josh Langley, giving the referee no option than to point to the penalty spot.
Substitute Brad Abbott confidently stepped up and to put the ball in the bottom corner despite Marosi getting a touch on it's way in.
As the game drew to a close both sides pushed for a winner and on 88 minutes it almost came early for Latics as once again a ball into the box proved Barnsley's achilles heel as their goalkeeper left it late to come and claim and could only tip the ball onto the bar.
Barnsley were living dangerously as they piled men forward, giving Latics the perfect chance to net a winner on the break.
An attack from the Tykes was broken down in Latics' box and cleared to Johnson on the half way line, he turned under pressure to release Angoy down the left wing who still had work to do.
The Spanish winger's eyes lit up as he dodged two challenges from oncoming defenders and continued his run from the touch line to the by-line.
Josh Sumner spotted the hard work done by Angoy and made a burst into the box to connect with the cut back across the box and seal a last ditch but deserved victory.
After the game Graham Barrow was full of praise for his side, saying:
"I think overall we deserved to win the game because we worked really hard for it.
"Josh (Sumner) does great to get in and finish for the winner after some great play from Jesjua (Angoy) for the assist."
Barnsley: Trialist, Patterson, Steade, Edwards (Shillito 62), Collins, Kilburn, Scott, Rooney (Abbott 55), Oates (McKnight 76), Clark, Silva
Latics: Marosi, Morris, Lynch, Chow, Langley (Wilson 90), Buxton, Sumner, R,Watson, Johnson, Redmond (Bingham 39), Phillips (Angoy 62)
Unused subs: Hare, Johnstone