#1 Bret Hart vs "Stone Cold" Steve Austin, WrestleMania 13

It seems odd to call one of the two matches perpetually in contention for greatest WrestleMania match ever a surprise in terms of match quality, but one detail about the match gave its combatants major qualms about their ability to deliver a quality product.
Austin has been very vocal on his podcast (and in interviews on others, like a stellar appearance on E&C's Pod of Awesomeness, where he and Hart dig deep into the details of this match) about the fact that he found out that his WrestleMania 13 match would be contested under Submission Match rules. Both he and Hart were livid, but for different reasons.
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Austin was frustrated that little to none of his offense lent itself to a submission match. He rarely, if ever, employed holds or worked a body part long enough to set opponents up for a signature hold, and hadn't ended a contest with a submission since his days as Ted DiBiase's Million Dollar Champion, The Ringmaster.
Hart, meanwhile, felt that removing pinfalls from a match took away the best bit of drama a false finish could provide, the "One! Two! NO!" of near-falls before the final three-count and its ensuing pop.
Further, The Hitman had, two WrestleManias prior, fought Bob Backlund in a submission match that would have to improve a great deal just to be considered bad.
In essence, Bret and Steve felt their match was snakebit from the start, to borrow a Bruce Prichardism.
The first part of saving this contest came in the finish room, where Austin, Hart, and Vince McMahon planned out Austin's refusal to quit, and Hart's relentless attack on his beer-swilling foe.
The second was a clandestine conversation between the two rivals over the fact that such an epic finish demanded blood, and Bret was willing to take the heat for pulling it from Austin's head.
Over the course of the match, Bret convincingly worked the legs and lower back to soften Steve up for the Sharpshooter, while Steve seemed bent on just causing the Canadian as much pain as possible, seemingly hoping for Hart to submit just to prevent any further beatings.
They were decisions made purely out of what their established characters would do, and they overcame both men's fears in the making of a five-star classic.