Stefan Scougall struck the only goal of the game after 23 minutes to secure a seventh successive victory for the Blades in all competitions.
While the FA Cup quarter-finalists are on a role, the result was a further blow to the Dons' fading play-off hopes.
Robinson said: "I'm not going to argue that we deserved to win it because we didn't play enough football to win it.
"We can't say we were dominant or classy in possession - far from that, we definitely huffed and puffed.
"They made sure players weren't running off them and blocked runners but because we were trying to be honest, they ran beyond our backline and scored a very well-worked goal.
"But the players were told on Friday and they just switched off.
"When there was no space to play we couldn't get around them and we couldn't get crosses in.
"We definitely huffed and puffed second half and had two really good chances, but I think to say we could've walked away with three points would be a little unfair on them."
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