Colchester 2 (Moncur 67, Porter 70)
Reds 3 (Hourihane 18, Hammill 40, Toney 60)
The Reds picked up three valuable points after a 3-2 win in Colchester, but were made to sweat as the hosts sprang a come-back after the Reds charged into a 3-0 lead.
Conor Hourihane, Adam Hammill and Ivan Toney bagged a goal each and the Reds managed to weather the second half storm caused by Colchester's spirited comeback.
A quiet start turned scrappy as both sides battled for possession in the middle of the park and neither side were giving anything away.
The first action of the game saw Barnsley come close twice in quick succession. A quick-thinking free-kick by Hourihane allowed Winnall to cross for Mawson whose header was well saved by Jones. The ball would eventually fall to Hammill who tried a placed volley at goal but he saw his neat attempt dip just the wrong side of the post.
Winnall himself then came close to opening up a chance on 15 minutes but he was just thwarted at the last second by Eastman as he looked set to go one-on-one.
Barnsley were on top and rewarded for it on 18 minutes. Sam Winnall was well played into the box by Toney and after seemingly being brought down by the 'keeper Jones, play continued allowing Conor Hourihane to steer in from 12 yards.
The Reds' passing was crisp as they completely took control of the game with swift movement of the ball making Colchester chase shadows.
Five minutes before the break saw Adam Hammill slipped in down the left-hand side by Sam Winnall and the winger went one-on-one with Jones. The winger made no mistake as he calmly slotted home past Jones.
The little Colchester offered came in the form of a long-range Marvin Sordell shot that was dragged well wide on 44 minutes.
The home side made a change at the break as big striker Chris Porter replaced midfielder Joe Edwards, as Caretaker Manager Wayne Brown looked for a way back into the clash.
The temporary boss got an immediate response as first Porter forced Davies into a good block one-on-one before Eastman landed a header onto the crossbar all within two minutes of the restart.
Full-back Brindley probably should have done better on 50 minutes when he dragged wide from a tightening angle as the hosts continued with their positive response.
On the hour Barnsley's quality shone through as the fairly quiet Watkins danced into the box from the right and his cross seemed too awkward for Toney but the striker powered a header into the far corner from eight yards. It was a great effort from the on-loan Newcastle man who made it two in two.
On 67 minutes Colchester pulled one back. Moncur was threaded in by Porter and the midfielder made no mistake as he slammed in from a fairly tight angle.
Three minutes later it was 3-2. The Reds were raging as Marley Watkins was dragged to the ground but play continued as the U's broke. Harriott's cross was well taken down by Porter who smashed in via the hand of Davies.
Adam Davies came to his side's rescue on 72 minutes as he scrambled across his goal to deny Harriott's long-range punt.
Barnsley had to slow the game down and pick and choose their moments to attack on the break.
It should have been 3-3 on 84 minutes but somehow Richard Brindley's deep cross was turned wide by Porter at the far post of an open goal.
Four minutes later the home side came so code again. Harriott's shot was deflected into Sordell's path but he scuffed wide from only eight yards and just Davies to beat. Just before the Fourth Official showed four added minutes, Moncur Bent a wonderful effort just wide of the far post. Barnsley were sweating and desperate for the full-time whistle.
Hammill came fairly close to a solo wonder goal but the final whistle did finally come as Barnsley picked up the points.
Colchester: Jones, Brindley, Eastman, Elokobi, Briggs (Vincent-Young 66), Gilbey, Edwards (Porter 46), Massey (Bonne 75), Moncur, Harriott, Sordell.
Sub: Parish, Kent, Szmodics, Lapslie, Bonne.
Reds: Davies, Wabara, Mawson, Nyatanga, A. White, Watkins, Pearson, Hourihane, Hammill, Winnall, Toney.
Subs: Townsend, Roberts, R. Williams, Isgrove, Bree, Jackson, M. Smith.
Referee: Stephen Martin.
Attendance: 3265 (288 Reds)