The U's goal came in bizarre fashion when James Chambers' clearance hit Craig Eastmond and flew past Richard O'Donnell, the Essex outfit subsequently winning the game and ending the season in 16th place after being relegation candidates for much of the season.
"It's a positive way to end the season, and another positive away performance," Dunne told reporters after the game.
"Three wins and a draw kind of mirrors the form just before Christmas when the weather closed in. As a group, we have managed to keep everyone fit and the resulrts have managed us to stay in the league and finish strongly.
"I'm not really bothered about the slice of luck with the winner. All season we have played well and yet come away from games with nothing. If this word 'luck' wants to appear on the final day of the season, then so be it."
Tranmere Rovers and Carlisle United will join Shrewsbury Town and Stevenage in League Two next season after suffering relegation from the third tier on the final day.