As Borussia Dortmund and Real Madrid prepare for their ultimate showdown, both sides know there is no room for error.
The two will face off at Wembley Stadium in the Champions League final on Saturday 1 June from 8pm, live on talkSPORT.
In a game of such magnitude, every right decision is crucial and every wrong decision could be costly.
And if they want an example of just how much one decision can haunt a club, they need only look to Tottenham.
For Spurs fans, the memory of that fateful day in the Metropolitano Stadium in Madrid back in 2019 when they lost 2-0 in the Champions League final to Liverpool is still a painful one.
The north London side had made it to the final of the Champions League for the first time in their history after a remarkable turnaround in their semi-final clash against Ajax.
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Their ability to continually grasp victory from the jaws of defeat throughout the competition gave them a sense of invincibility as they headed into the final against Liverpool.
Alas, it was a false sense of invincibility.
When the then-Tottenham-manager Mauricio Pochettino announced the team, there were more than a few raised eyebrows.
On the list was star striker Harry Kane - a player who at that point had not played a competitive game of football in nearly two months.
The England captain had been battling a ligament injury in his left ankle, desperately hoping to make a recovery in time for what could well have been one of the biggest games of his career.
In the end, his manager made the perhaps unexpected decision to start him in the huge game - despite his lack of recent playing time.
But more surprising still was that the hat-trick hero of Spurs' semi-final victory over Ajax, Lucas Moura, was demoted to the bench.
It felt like a cruel outcome for the player who had orchestrated Tottenham's path to the final.
The Brazilian forward was ultimately only given 24 minutes to make an impact as a substitute in their 2-0 final defeat to Jurgen Klopp's Reds.
By that point, it was all just too little, too late.
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"You want to create a drama, but it's not a drama," Pochettino would say after the game when asked about starting Kane.
"It's just a decision. He finished the game fresh. I promise, my decision involved a lot of analysis. I don't regret my decision."
But Kane had completed just nine passes and taken one shot during his 90 minutes on the pitch against Liverpool.
Perhaps it was his fitness, maybe the occasion got to him, or had Liverpool's defence had just marshalled him superbly.
But there is a question that haunts Tottenham fans to this day: would the outcome have been different if Moura had started instead of Kane?
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We will never know.
But as Kane, now denied victory at Bayern Munich too, is forced to watch another piece of silverware pass him by, Dortmund and Real Madrid will both be aware that this final could become their club's greatest moment - or it could become their most haunting memory.
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