Arbroath blew the chance to guarantee a play-off spot after a poor 1-0 defeat to East Stirling.
The veteran striker turned and fired his shot past the goalkeeper, only for the ball to rebound off the far post.
And East Stirling went on to take the lead in the 35th minute when Kevin McBride's free-kick deflected off McMullen and fell to David Nicholls, who fired home with precision from 25 yards. Andrew Brand fired a shot just over the crossbar shortly after the restart.
Arbroath lacked creativity in attack throughout the second half, with the best chance falling to Tosh, who headed wide from Paul Watson's cross on the hour mark.
ARBROATH boss John McGlashan gave his players both barrels after they slumped to defeat against East Stirlingshire.
The Red Lichties turned in a woeful display in front of a subdued home support, as a superb Davie Nicholls strike proved the difference between the sides. The Arbroath gaffer knows his team will have to raise their game dramatically in the next two matches against champions East Fife and second-placed Stranraer if they are to secure a play-off place.
Elgin City's defeat to Stranraer meant an Arbroath victory would have secured a fourth place finish, but now they face a nervous 90 minutes in Methil.
McGlashan said, "We are massively disappointed with the result. Goals change games, and we hit the post early on, which would have made a difference had it gone in. Then they went on to score and we had a few half chances here and there, but ultimately we have been in this situation for the last month or so.
Our performances have been average at best, but we have managed to pick up points along the way.
We have more than a few players who are struggling to find their form at the moment, and it's hard to carry one or two in any game, but when you have got three or four—maybe even more at times—it's impossible.
I've been there myself as a player, but the only way you can overcome it is to look at yourself in the mirror and get yourself right back into the groove. You've got to fight off your demons and prove next week that you are better than that."
Arbroath never got going during a dull 90 minutes, but Davie Nicholls sent the Shire fans home happy with a tremendous first-half strike. The home side almost took the lead on 19 minutes when a Paul Tosh drive crashed off the post, but that was as good as it got for McGlashan's men.
Shire never looked flustered, and took the lead on 35 minutes when Nicholls cracked home an unstoppable shot from the edge of the area.
The home support stood in silence as their team continued to disappoint, and only the referee's whistle prevented Shire from extending their lead when a Joe Savage header was chalked off for an earlier foul.
Arbroath's best chance of rescuing a point fell to Nicky Smith, but his crisp volley flew straight into the arms of Gary O'Connor, who was happy to record his third clean sheet in a row.
Shire boss Jim McInally said, "It's going to be hard to get off the bottom of the league, but what a chance we have given ourselves. We could have passed the ball better, but our work-rate was phenomenal."