The formation of the Old Lady could vary from 3-4-3 to 4-2-3-1 but Allegri has already chosen who will play from the first minute and has already informed the team about it.
Ajax overcame Panathinaikos in 1996 and Inter Milan managed to beat Bayern Munich in 2011 - both, however, only needed to recover from a one goal deficit.
"We have to stay confident, try to play our game and put on a good performance and if we score at the start of the game, maybe that could change things", he said. "Monaco have nothing to lose, they have quality players and are playing for a place in the final".
Mario Mandzukic opened the scoring in the 33rd minute, sneaking in at the far post to steer Dani Alves' cross past Danijel Subasic at the second attempt...
Juventus forward Paulo Dybala limped off during Saturday's 1-1 draw at home to Torino, which ended his side's run of 33 consecutive home league wins, but coach Massimiliano Allegri said it was just a case of cramp.
"Now we are in the crucial phase of the season because we have not won anything yet".
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"Monaco are a side with great talent and we have absolutely not yet sealed our qualification".
"We need to be fully focused for the match", he said. Claudio Marchisio came on in his stead, and the midfielder enjoyed a terrific showing in the semi-final against the principality side.
In terms of the home side, boss Massimiliano Allegri makes just the one adjustment from last week's first-leg triumph in the principality - Sami Khedira returning from suspension to take over from Claudio Marchisio. Juventus have kept many clubs scoreless in the Champions League this year, not letting in a goal in 621 consecutive minutes. Overall, Juventus have only let in two goals over the duration of the Champions League.
Beaten 3-1 by Barcelona in Berlin in the 2015 final, Juve have an excellent chance to reach the showpiece match again when they host AS Monaco on Tuesday holding a 2-0 lead from the away leg of their semi-final tie. But there aren't many regrets from this European campaign.
Buffon was beginning to look unbeatable as he sprawled to deny Mbappe one-on-one but the teenager would have his goal soon after as he turned in from inches after Joao Moutinho got to the byline from a short corner.