After Joe Pigott had cancelled out Cauley Woodrow’s opener, goals after half-time from Kieffer Moore, Mamadou Thiam and Cameron McGeehan sealed another away-day victory for the Reds.
“I said to the squad at half-time that this was a test for us,” Stendel said. “You have to work hard to get what you want. But when we went 1-0 in front we were a little bit lazy and we gave away the ball too easily. Wimbledon were better than us at that point, they made it 1-1 and had a chance to take the lead so we had a bit of luck there.
“We needed a reaction in the second half, that’s what we told the players, and we scored early and then we had more control and played more like a team at the top of the table.”
Barnsley took the lead when a corner found Woodrow, who finished with aplomb on the turn with a first-time strike. Wimbledon entered the game with the division’s worst attack but breached the league’s meanest defence as Pigott flicked home Andy Barcham’s free-kick.
The hosts should have led at the break but Jake Jervis missed a tap-in at the back post, while Dons keeper Aaron Ramsdale denied Kenneth Dougall and Alex Mowatt.
Jervis’s miss proved costly when Moore restored the visitors’ lead with a towering header from Mowatt’s cross.
Thiam then made it 3-1 with a rocket into the top corner after Moore had beaten two Wimbledon defenders to set him up before McGeehan compounded the Dons’ misery late on.
AFC Wimbledon: Ramsdale, Watson, Nightingale, Oshilaja, Thomas, Pinnock, Kalambayi, Seddon, Barcham (Connolly 59), Pigott (Wordsworth 69), Jervis. Subs not used: Wagstaff, Hartigan, Garratt, Wood, McDonnell.
Barnsley: Davies, Cavare, Pinnock, Lindsay, Ben Williams (Pinillos 67), McGeehan, Thiam, Mowatt, Moore (Adeboyejo 80), Brown, Woodrow (Dougall 42).
Referee: Neil Hair (Cambridgeshire).