Buffon showed a fortnight ago that he still has the reflexes to go with his glittering reputation.
Buffon showed a fortnight ago that, at 38 years old, he still has the reflexes to go with his glittering reputation on the way to stopping Alexandre Lacazette's 35th minute spot-kick at Stade de Lyon and helping Juve clinch a precious 1-0 win.
Although Allegri praised the Juve shot-stopper, he quickly underlined the importance of securing a win on Wednesday that would secure Juve's last 16 ticket and keep them on track to finish top of Group H.
"For me, Buffon represents world football. He's an extraordinary player who, for the past 20 years, has been the best of the bunch," Allegri told media in Turin.
"Tomorrow is a really important game for us because we can qualify. We absolutely have to follow up on what we achieved at Lyon last time out.
"Our objective is to get to March and still be competitive. But to do that we have to get past the first round and we haven't done that yet, so tomorrow's game is still a delicate for us.
"It won't be easy, because Lyon are coming off a good away win at the weekend (at Toulouse). It's up to us to take our responsibilities, but also show Lyon the respect they deserve."
Lyon need to beat Juventus to have a realistic chance of remaining in the competition, but the statistics are firmly against Bruno Genesio's men.
They have lost their last four games against Italian opposition and lost to Juventus both home and away when the sides met in the 2013-2014 Europa League quarter-final.
Juventus, meanwhile, have won four and drawn one of their last five encounters against Ligue 1 sides and are amid an 18-match unbeaten run at home in UEFA competition.
With Argentine forward Paulo Dybala and Croatian youngster Marko Pjaca both sidelined with injury, Allegri has little choice but to deploy Mario Mandzukic up front with Gonzalo Higuain.
The pairing was tested out only recently, but despite the need "for a few improvements", according to Higuain, the Argentine said he has no complaints playing alongside the big Croat.
"With Mario I get on great (playing together)," said Higuain, who hit the winner in a 2-1 defeat of former club Napoli in Turin on Saturday.
"Obviously we've only played a few games together, but we're doing well and looking to get better over the rest of the season."
Higuain's move to Juventus for an Italian transfer record fee of 90m euros in the summer may have left thousands of fans disappointed in Naples, where he scored a Serie A record of 36 goals last season.
But it has moved him considerably closer to realising his dream of winning the Champions League.
Juventus, beaten 3-1 by Barcelona in the 2015 final, failed to get past the group stage last season, but Higuain added: "I hope we do better this year than last year, and that we can go all the way."
Claudio Marchisio is set to start alongside fellow midfielder after making a full recovery from a serious knee injury, although Allegri is set to reshuffle his defence after Giorgio Chiellini was sidelined with injury during the Napoli game.