MK Dons suffered their first home defeat of 2012 as 10-man Yeovil boosted their chances of avoiding relegation.
Gavin Williams put the Glovers ahead with a deflected effort past David Martin, before Dean Parrett was sent off after two bookable offences.
The hosts' Dean Bowditch had a spot-kick saved by Sam Walker after Luke Ayling had handled in the penalty area.
Both sides ended with 10 men as Dons midfielder Stephen Gleeson was sent off for violent conduct in stoppage time.
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MK Dons manager Karl Robinson told BBC Three Counties Radio:
"The challenges this game throws at you are remarkable and it's about how you respond.
"We win games and draw games and brush ourselves off and go again.
"I don't think you can question any of the players and I thought they did enough to win three or four games. But we've got to be more ruthless in front of goal. It's as simple as that."