The Potters hit Barnsley with a two-goal first-half blast and were cruising to their second win of the season until the remarkable turnaround in the final 18 minutes of the game.
Stoke went in front after only three minutes when Peter Sweeney swung in a corner for Michael Duberry to head on at the near post and Clint Hill powered in the header past stranded Tykes keeper Nick Colgan.
Three minutes later Mamady Sidibe went close to adding a second but his header from Luke Chadwick's cross from the right was inches over the top.
And as City had Barnsley on the rack, Sidibe charged down the right and swung a low cross for his striker partner Vincent Pericard, but he was just short of a scoring connection.
Barnsley responded but a Paul Hayes shot on the turn was easy for keeper Steve Simonsen. And the keeper made another comfortable stop when Martin Devaney cut inside and drilled in 20-yard effort with his left foot.
And when Dale Tonge aimed a cross from the right, Brian Howard's header went close from ten yards out.
But Stoke's height and power was involved when they stretched their advantage after 22 minutes.
Sweeney's cross from the left exposed the home side's lack of inches and Pericard headed back unchallenged and picked out Chadwick who drilled a cool shot in from 12 yards.
As Barnsley threatened on the break Paul Hayes twisted and turned and fired a shot wide from 18 yards.
But in an impressive second-half fightback Barnsley carved out a string of chances after a half-time roasting from manager Ritchie.
Hayes hit a low free-kick through the Stoke wall but Simonsen saved smartly and then a low shot from long distance from Marc Richards was only just wide of the target.
But Barnsley's persistence paid off handsomely when they eventually forced a breakthrough.
Substitute Tommy Wright rifled in a 72nd minute effort a mere four minutes after coming off the bench.
Just three minutes later Hayes stretched out a foot to guide in a Devaney cross from the right to equalize, as Barnsley continued to enhance their growing reputation as comeback specialists.