Barnsley have secured automatic promotion to the Championship after both Portsmouth and Sunderland lost on Tuesday evening.
Portsmouth lost 3-2 at home to Peterborough United - with ex-Red Ivan Toney netting twice for Posh – while Sunderland were beaten 2-1 at Fleetwood Town.
The Reds are now four points clear of Portsmouth and six ahead of Sunderland with just one match remaining so cannot be caught.
This caps an outstanding season for Daniel Stendel's side who have smashed club records for league points and clean sheets while equalling a club record 20-game unbeaten run and going unbeaten all season at Oakwell.
They will now travel to 16th-placed Bristol Rovers on Saturday, level on points with leaders Luton Town who they could still beat to the title.
