Adams watched strikers Jake Jervis and Yoann Arquin waste great chances to notch their first points of the league campaign before substitute Chris Erskine took advantage of a mistake by County keeper Antonio Reguero.
Jervis had earlier cancelled out a goal from Nadir Ciftci which had put the home team ahead on 19 minutes.
Adams said: "I think Dundee United have stolen the three points. I don't think anyone can have any doubts about that. I thought we played really well in the second half.
"We've had two open goals and not taken them. The two strikers - Jervis and Arquin - should both score with the chances they had.
"It's been the story of our season that when we haven't taken our chances the other team have scored.
"They scored against the run of play after Scott Boyd lost his man and then our keeper Antonio Reguero did a bad punch for the second goal.
"It's been disappointing but performance-wise and the way we took the game to Dundee United especially after the break was encouraging. But it's not the end of the world.
"We just need one win to get our season going. That's the way we're looking at it."
United manager Jackie McNamara feels his side responded well to last week’s hammering at Celtic Park, which remains their only defeat of the season.
McNamara said: "It's a good victory for us. It gives our fans something to shout about after the disappointment of losing the way we did to Celtic the week before.
"I'm really pleased for Chris to get the winner. His attitude has been first-class and he's at it mentally.
"We had plenty of chances even though we only scored two goals - but the start we've made to the season overall is still very pleasing for us."