And this victory for Watford means Graham Taylor's team are now within one game of returning to the top flight of English football for the first time in 11 years.
Not that it should ever have got that far as Birmingham, even when reduced to 10 men after 55 minutes had enough chances to settle the game in normal, let alone, extra time. Yet on a night of extraordinary highs and lows and commitment from both sides, there was a certain inevitability about who would have to suffer the disappointment and who would enjoy victory.
Dele Adebola put Birmingham ahead on the night and levelled the tie after just one minute and 50 seconds and that should have set the stage for the home side, themselves out of the top flight for 13 years, to cruise home. But Taylor's men are made of stern stuff, and despite barely creating a decent chance over this game, they never wavered and they did not let the home side through again.
Birmingham were trailing 1-0 from the first leg, and with a place at Wembley at stake, Francis decided to gamble from the start. And that meant he picked the top scorer Adebola, for his first start in six games, alongside Paul Furlong and Peter Ndlovu in a three-man strike force.
Poor Watford did not know what had hit them, when with not even two minutes gone at a sell-out St Andrew's, Bryan Hughes headed the ball back in to the penalty box from a poorly cleared corner, a pass that Ndlovu latched on to, and when his lob went over the goalkeeper but hit the post, Adebola was on the goal-line to make sure of the goal as Steve Palmer tried in vain to clear.
It was Ndlovu in particular who was causing havoc down Watford's inside- right channel, with another of his insistent dribbles and before Watford could stage any sort of reply, they almost found themselves two behind after 13 minutes, when an inswinging corner from Hughes was met with power by Gary Rowett, but the full-back sent his header just over Alec Chamberlain's bar.
Yet after their scintillating start to the match, Birmingham then suffered a setback 10 minutes into the second half, when David Holdsworth was sent off for his second yellow card. After what had been a mean-spirited first half, with players being booked for elbowing offences, it seemed a dismissal had been on the cards of the referee David Pugh from early on.
But with normal time almost up, Ndlovu missed two chances in the space of two minutes, which if he had converted either of them would have sent Birmingham to Wembley but the Zimbabwean saw both shots blocked by Chamberlain.
Yet Watford almost stole in and a cross was swung over from the right which found Tommy Mooney throwing himself forward to volley at the far post but with injury time being played, his effort went over the crossbar with Kevin Poole helpless.
Furlong went extremely close to settling the game in extra time, as Gary Rowett sent in a cross but Furlong's header was well saved by the Watford goalkeeper.
That was the cue for the shoot-out, that saw Holland miss with the 14th kick of the night after 11 consecutive penalties had been converted successfully. Furlong, for Birmingham, and Palmer for Watford missed their kicks, but Birmingham fans will long remember Chris Holland, and all for the wrong reasons.
Birmingham City (4-3-3): Poole; Rowett, Holdsworth, Johnson, Grainger; McCarthy (Purse, 57), O'Connor (Bradbury, 99), Hughes; Adebola (Holland, 64), Ndlovu, Furlong.
Watford (4-4-2): Chamberlain; Bazeley, Kennedy, Page, Palmer; Gibbs, Ngonge (Hazan, 88), Hyde, Mooney; Johnson; Wright (Smart, 88). Substitute not used: Day.
Referee: D Pugh (Wirral).