Wigan boss Malky Mackay has said the red card for second half substitute Callum McManaman was a turning point at The DW Stadium.
The midfielder was given his marching orders shortly after his introduction from the bench and from that point onwards, the Latics were forced to cope with relentless Wednesday pressure.
And the hosts could not hold out as Atdhe Nuhiu powered home his header with 13 minutes left on the clock.
Mackay said: “We were in fairly good control of the game and as it was going on I thought we were going to kick on.
“We had ten shots but obviously we went down to ten men and that’s not easy to take.
“After that, we were always climbing up hill and we lose the goal; we even have the one at the end where it hits the inside of the post and then there’s a scramble and we don’t manage to put it.
“First half we were very comfortable and second half we were up until the sending off and even then, we had two chances with James McClean and then the header as well.
“It’s these fine margins that are costing us at the moment and it’s something we’ve got to turn round.”