Andy Ritchie's team had suffered a 2-0 defeat at one of their bogey sides Doncaster at the weekend, and it was another side that they struggle to beat who denied them all three points at Oakwell.
The Vale equaliser came against the run of play. Substitute Jeff Smith delivered a firm cross from the left and while Barnsley full-back Paul Heckingbottom failed to get off the ground Michael Cummins rose high to send a soaring header past stranded keeper Nick Colgan and into the far corner.
Just six minutes earlier, Tykes substitute Brian Howard had seen his delightful chip from 18 yards come back off the crossbar. Had that gone in Barnsley would have been two up and home and dry.
The home side also had most of the play in the first half, with Antony Kay looking far more confident and composed in his more customary position at centre-half.
Paul Hayes meanwhile looked far more of a threat up front and, on seven minutes, he did well to wriggle his way into the box but fired over the top.
Martin Devaney then delivered a fantastic low cross on 13 minutes but there was no-one in the six-yard box to take advantage.
Barnsley came close to making the breakthrough eight minutes before half-time when Stephen McPhail's in-swinging corner flicked off a Vale defender but struck home forward Marc Richards on the line.
Richards tried to swivel and force the ball home but was crowded out by three visiting defenders.
Richards spurned a good chance on 55 minutes but was fortunate to see the offside flag raised, but two minutes later Barnsley did go in front.
Devaney's low ball into the box struck Richards and fell kindly for Hayes to clinically dispatch his 11th goal of the season.
Unfortunately it wasn't enough for the home side as Cummins struck late on.