The league leaders maintained their five point advantage in the top of the table clash with the 94th minute equaliser which keeps Cove on course for the title with five games to go.
Hartley had briefly looked away from the action after a frustrating afternoon but as he turned back, so did the tide for his team as he caught the looping strike sailing over Max Currie to spark wild celebrations in the away dugout.
"I just felt it was one of those days, it wasn’t going for us and we threw balls into the box and they were clearing things, defending well,” said Hartley.
“Then, when you ask for a little bit of quality Fraser steps up with an unbelievable finish and we had to celebrate together.”
The gap looked set to close to two with Airdrie holding the one-goal lead from their first attack, but Cove are assured top spot regardless of next weekend’s results.
"It is a massive point - we play next Sunday, Airdrie play on Saturday and that could really have turned the tide,” added Hartley. “We won’t take anything for granted."
It didn’t quite become one but the noisy 1650-strong support on both sides of the stadium gave it the feeling of a league decider and cooked up an atmosphere befitting one. Shay Logan conducted the away support at kick-off and even conceding early didn’t lower their volume – but Airdrie’s turned up.
A burst down the left from Adam Frizzell and cross into the six-yard area set up a chance for Callum Gallagher and though McKenzie saved the initial effort Gaby McGill pounced and had the final touch over the line.
It wasn’t the only uncertainty in the Cove box caused by Airdrie’s attack but the only one they took. Callum Smith blazed an awkward volley over and Gallagher headed a clipped Craig Watson cross straight at Stuart McKenzie in what could have been valuable goals.
The misses came back to haunt Airdrie in the most dramatic and spectacular way.
Cove were being out-played by Scott Agnew and Dylan Easton in the middle of the park but gaining ground via Shay Logan on the right, the veteran firing narrowly over Max Currie's bar.
The frustration began to tell on the away support, unused to such struggles, but their team were the more threatening in the second half with Rory McAllister on to partner Megginson and Fraser Fyvie dropping in to stiffen up the midfield.
They appeared more settled, and the second half well-matched, but Airdrie’s first half profligacy bit in the most painful way. Seconds from seeing the league deficit cut from five points to two Fyvie’s 25-yard stunner looped over Currie and sent the away support into raptures, crucially keeping their advantage intact with five games to go.
Ian Murray admitted: “I thought we were the better side and it’s a cruel blow to us in terms of catching Cove but I’m proud of the players and supporters who backed us right from the warm-up.
"We are not finished. It’s not in my make-up or the team’s and we’ll go to the bitter end."