The 18-year-old, with a handful of reserve games behind him, came off the bench and immediately saved Keigan Parker's spot-kick on the stroke of half-time in a fiercely fought and highly entertaining game at Bloomfield Road.
The opening 40 minutes had been relatively quiet, but a decision in the 43rd minute sparked an amazing two minutes of football which changed the game.
Firstly Blackpool's Rick Wellens was given his marching orders when he was adjudged to have handled Julian Bennett's header on his own line. Matt Fryatt, Walsall's normally reliable spot-kick specialist, stepped up and saw his shot well saved by Lee Jones.
Blackpool were immediately on the counter attack. Martin Bullock played in Parker who was about to cross from the byline when he was brought down by Ian Roper to the fury of Walsall keeper John Murphy.
Murphy immediately confronted Parker prompting a 20-man brawl and earning himself a red card.
Parker then saw his penalty saved at full stretch by young Coleman before the half-time whistle sounded.
With two fewer men on the field the second half was an open affair and Blackpool finally found a way past Coleman on 57 minutes when Bullock teed up Murphy who finished coolly from 12 yards out.
Amazingly that was not the end of Coleman's heroics and, when Parker was nudged over in the penalty area by Neil Emblen, the youngster again had a chance to show off his penalty saving prowess.
Keith Southern took the spot-kick and Coleman was once again equal to it, but the shine was taken off this particular stop by the fact that Southern knocked in the rebound to complete the scoring.