A combination of his side’s poor start as well as a controversial refereeing decision ensured that Forfar manager Dick Campbell had a miserable St Valentine’s night at Airdrie as his side lost ground in the title race.
After a minute’s silence for Forfar youth player Jack Syme was observed the Loons fell behind after just five minutes.
A long kick from goalkeeper Andy McNeil reached deep into visiting territory and Marc Fitzpatrick swept home a Jim Lister cut back from 18 yards.
Any chance Campbell’s side had of taking something home with them was gone midway through the first half after on-loan Dundee United midfielder Scott Fraser sliced open their defence with a back heel.
Bryan Prunty ran through on goal with Gavin Malin in pursuit and the striker crashed to the ground after he had lost control of the ball, Malin having made the softest of brushes against him.
Referee Greg Aitken pointed to the spot and immediately dismissed Malin while Prunty ignored any controversy over the award to stroke home the spot-kick and complete a century of goals in his career.
Forfar battled manfully for the remaining three quarters of the game before going further behind when Fraser had time to pick his spot from a Lister pass to give the hosts a three-goal advantage.
Michael Travis scored a consolation effort before the end from close range after McNeil had spilled a driven Stephen Husband free-kick.