Airdrie made it 16 League One games unbeaten and heaped pressure on Cove Rangers with a comfortable 2-0 win at Bayview against East Fife.
The Diamonds dominated the early stages without creating anything too clear cut, with Calum Gallagher going close with an ambitious lob.
Dylan Easton then hit the bar from a free-kick as momentum built for away manager Ian Murray and Gallagher eventually put the Lanarkshire side in front before half-time, making it a brace after the break.
Stevie Crawford's team had fought back and Hearts loanee Finlay Pollock was denied a crucial goal by the post before the second away strike squashed their comeback charge.
Murray's side are still second in the third tier, but with first-placed Cove Rangers not playing until Sunday at Queen's Park, the gap has been cut to just two points with four games to go. East Fife are seven adrift at the bottom.
Airdrie were missing key man Rhys McCabe as Josh Kerr came into the Diamonds defence following their 1-1 draw with leaders Cove last Saturday.
Remaining five points behind Paul Hartley's side with five to play, a victory at Bayview was paramount to their title ambitions, having already secured a promotion play-off spot.
They almost had an audacious opener through Gallagher after eight minutes. The striker noticed goalkeeper Jude Smith off his line and his effort from around 40 yards out flew narrowly over the bar.
Easton's curling a minute later wasn't quite as spectacular but his curling shot went wide. Ryan Blair perhaps could have done better with a home chance on 16 minutes as a warning shot was fired.
There were soon claims for a Diamonds penalty on 19 minutes with Smith coming out of his goal and colliding with Gabby McGill, but nothing was given.
Callum Smith was handed League One's Player of the Month award for March after five goals for Murray's men, but his tame effort on 23 minutes was never troubling East Fife.
It was all Airdrie in terms of chances though and Gallagher's swing at the ball on 25 minutes was close to finding the bottom-left corner.
A key creator of goals for his team all season, Easton was unfortunate to score with a free-kick roughly 30 yards from goal on 28 minutes.
Smith really should have put the Excelsior Stadium side ahead on 36 minutes but his namesake in the East Fife goal did really well to stop it, before Gallagher's shot at the following corner was somehow denied.
Eventually the former Rangers forward would not be stopped as he stabbed home into an empty net after a sweeping away move.
It was the least they deserved after a rampant half where they could have been another two or three goals ahead with a rub of the green.
Adam Frizzell picked the Diamonds up from where they left off with a 52nd minute drive that soared narrowly over the crossbar.
It had become a bit more cagey though as both teams handed over possession cheaply. But East Fife never looked like posing much of a threat to the visitors they were entertaining.
Scott Mercer though was gifted a chance after Airdrie failed to clear a loose ball on 61 minutes, blasting a shot so wide it was kept in play near the corner flag. He only had goalkeeper Max Currie to beat from five yards out.
It had been dominant from the Diamonds but with East Fife knowing a loss could leave them seven points off the relegation play-off place, and 11 off automatic safety with four games to go, they started applying pressure.
Pollock should have scored on 64 minutes but struck the post, and the resulting corner caused trouble that was eventually averted.
The 71st minute killed any hope the home side had of mounting a comeback. Frizzell looked to have took too long with his cutback but Smith's shot was eventually bundled in by Gallagher, for his second of the day.
That sealed victory for Airdrie, who have not suffered a league defeat in almost five months.
East Fife XI: Smith, Watson, Higgins, Murdoch, Pollock (Slattery, 67), Swanson (Denholm, 67), Mercer (Healy, 77), Millar, Steele, Blair (Newton, 59) Connell.
Subs: Campbell, Walls, Semple, Higgins, Mackenzie.
Airdrie XI: Currie, Paterson, Kerr, Fordyce, Agnew, (Ritchie, 90), Gallagher (Afolabi, 88) Easton, Smith (Devenny, 90), Frizzell, G McGill (Allan, 82), S McGill.
Subs: Cantley, McDonald, Watson.
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