Small arrived for a month from Sheffield Wednesday then conjured up a stunning debut strike to sink the South Yorkshire side.
Small's gem from 20 yards was the highlight of dreary windswept shocker and came 20 minutes from the end after the Seasiders had held the home side at bay.
Blackpool keeper Paul Rachubka made a string of impressive saves as Barnsley, inspired by winger Adam Hammill who is on loan from Liverpool, looked poised to force a victory
Both sides found the fierce wind swirling around Oakwell tough to handle, but Blackpool managed to carve out two early chances that might have earned them a lead.
Small used the breeze to curl in a sweet cross that deceived Barnsley defender Rob Kozluk.
It dropped over the right-back and sat up invitingly for Joe Martin, who took a touch but then slammed his ground hugging angled shot wide from six yards to let the home side off the hook.
A minute later, Charlie Adam picked up the ball and darted to the edge of the Barnsley area but his raking effort was off target.
The Seasiders suffered a 20th minute setback when defender Danny Coid was forced to bow out after suffering a double whammy - injuring his leg in a challenge and suffering a bloody nose when his face hit a team-mate's boot.
Two minutes later, winger Hammill produced a super corner but Denis Souza's header hit a defender.
Another well crafted corner from Hammill - who spent a pre-Christmas spell at Blackpool - was headed down by Bobby Hassell and Hugo Colace volleyed a stinging shot that was halted by a brave block from Alex Baptiste.
Hammill tested the visitors with a shot that looped off Keith Southern and dropped just over the bar.
And in the dying seconds of the first half, his stunning free-kick carried on the breeze forcing a top class save from Rachubka.
Jamal Campbell-Ryce picked out Hammill with a cross-field ball and he cut in from the left before unleashing a super dipping shot that Rachubka did well to stretch and tip over.
Another dangerous corner from Hammill had the visitors in trouble as Small headed off his own line, but he was the hero at the other end 20 minutes from the end.
Blackpool keeper Rachubka preserved the win wit another super save after tipping over Campbell-Ryce's stunning late shot.