Forfar boss Dick Campbell was furious after an insipid display which saw his side drop important points in the battle for the League One title.
Stranraer, Morton and Brechin all won, and Campbell was annoyed that his side lost to a hungrier team, and at the lack of goal threat.
The Loons manager said: “We have lost to an Ayr side who were battling for their lives as they are desperate to avoid relegation.
“We started well and had them under pressure for the first 30 minutes, then we lost a poor goal against the run of play.
“From our point of view it was a very bad goal to lose as we gave Jordan Preston far too much space at the edge of the box. We made it too easy for Preston and it was at a time when we were on top.
“However, we never did enough in front of goal.
“The better team won as they were fighting for everything and, although we had a lot of the play, their keeper never had a save to make.
“How can we say we deserved to win when we never even managed a single shot on target?
“All three of the other teams at the top have won while we have lost, so I am not exactly overjoyed with today’s work.”
Forfar started positively and had the bulk of the early play, but found Ayr well-organised in defence.
Chris Templeman claimed Nicky Devlin pushed him in the box after Martyn Campbell’s cross but the referee was not interested.
The Honest Men went ahead on 34 minutes. John Paul McGovern nodded the ball to Preston in space at the edge of the box and he fired into the bottom right corner.
On 48 minutes Forfar sub Danny Denholm’s cross from the byline was bravely held by David Hutton, with Omar Kader ready to pounce.
The Loons almost grabbed a point when Martyn Fotheringham sent a 30-yard shot off the bar with his first touch 30 seconds after coming on as a sub on 66 minutes.
Campbell may not have been impressed with his team, but Ayr’s match-winner Preston had words of consolation.
The 19-year-old, on loan from Blackburn Rovers, said: “We knew this was going to be a battle against a physical team, and Forfar were dangerous and very difficult to play against.”