Barnsley maintained their unbeaten start but were held to a goalless draw at Oakwell.
“We perhaps should have been a bit more ruthless,” said Reds No 2 Andreas Winkler. “But, in the second half, we still showed a very positive attitude against a very strong, physical opponent and it was not easy.”
The Reds were knocked off top spot as a result of the draw.
They started strongly and the first chance fell to Brad Potts, who fired over after Dimitri Cavare had won possession.
Dons responded with Tom Soares forcing Adam Davies into a good save with a long-range effort but Scott Wagstaff nearly sliced the ball into his own net as Barnsley pressed.
Kwesi Appiah went close for the Dons when he whipped a free-kick just over before Barnsley had a penalty appeal rejected after Tom Bradshaw went down.
On the stroke of half-time, the Reds counter-attacked through Mamadou Thiam and he squared for Alex Mowatt, who shot wide from the edge of the area.
Potts was also off target after the interval and Appiah could have put the Dons ahead in the 56th minute but he shot straight at Davies after good link-up play with Scott Wagstaff.
Tom King then saved from Liam Lindsay at the other end before Appiah was denied an opener by the offside flag.
Reds chief Daniel Stendel used all three substitutes to shake things up. Barnsley’s best chance came when Kieffer Moore ran onto a long ball before crossing to Bradshaw but his shot was blocked by Deji Oshilaja.
Barnsley: Davies, Cavare, Pinnock, Lindsay, Pinillos, Potts (Jordan Williams 75), Dougall, Mowatt, Bradshaw (Moncur 65), Moore, Thiam (Adeboyejo 83). Unused substitutes: McGeehan, Walton, Jackson, Ben Williams.
AFC Wimbledon: King, Watson (Sibbick 83), Oshilaja, Nightingale, Purrington, Wagstaff, Soares, Trotter, Barcham, Appiah (Pigott 80), Hanson. Unused substitutes: Pinnock, Garratt, McDonnell, Rod McDonald, Wordsworth.
Referee: M Coy (County Durham).