Having seen his team take a first-half advantage and fall apart yet again, so reminiscent of many performances this season, the United midfielder came on as substitute to smash a tremendous 40-yard volley into the roof of the net.
It gave Falkirk little to take away from the game apart from the consolation of having turned in a credible second-half performance that deserved a point.
After so much hype during the week, following Gordon Chisholm's not unexpected departure, the game itself began with much huff and puff from the Tangerines without really threatening Allan Ferguson's goal.
That was until the tenth minute when the in-form Collin Samuel swung in a tantalising cross for Stuart Duff to volley over from 14 yards.
But it was the visitors that had the best chance of the opening quarter when Stephen O'Donnell took advantage of yet another woeful error by Alan Archibald and glided past the struggling David McCracken before thumping the ball off the base of the post from 16 yards with Craig Samson stranded.
Five minutes later, the keeper again saw a cross-cum-shot fly off the bar from Alan Gow on the left flank when the keeper had left the ball following a call from Paul Ritchie that it was going over.
United were sluggish and, despite new manager Craig Brewster sitting in the stand, they showed little encouragement that the future of the club remained with the 11 players in Tangerine shirts.
The visitors, yet again, created another chance in the 26th minute with Lima's low 20-yard shot forcing Samson to turn the ball around the post.
The Tangerine faithful were desperate. It took until the 29th minute for the on-loan Charlie Mulgrew to thump in a 25-yard free-kick that forced Ferguson to tip over.
The game needed a lift and it came from the brilliance of David Fernandez in the 35th minute with a fantastic chip.
Seeking some support from his AWOL colleagues, the Spaniard saw Ferguson off his line and elected to brilliantly lob the ball over the keeper from 18 yards rather than pass.
With half-time approaching, it was almost two. Wonderful wing work from Mulgrew led to Grant Brebner pulling off a magnificent save from Ferguson's net-bound header from three yards.
The second period gave the fans little to shout about until the 70th minute when the game turned. Fernandez missed an easy chance with only the keeper to beat after Samuel had created the opportunity.
Falkirk then set about United's fragile defence and, as has happened throughout the season, it was not surprising that the visitors equalised through shambolic defending from the home defence.
Daniel McBreen nodded in when a hoofed clearance from Archibald, under no pressure, had panic written all across it.
It was now all Falkirk. Brewster must have cringed as he watched his beloved United, realising he has a massive job ahead of him to turn this team around.
It looked as though there was only going to be one winner and that was Falkirk - until McInnes' late rescue act.