Rio Ferdinand and Luis Garcia say Alisson's performance on Tuesday night proved the goalkeeper is more than worth the transfer fee paid for him this summer.
Liverpool broke the bank to sign Alisson from Roma this summer, paying a then world-record fee of €62.5 million (£56m) to sign the goalkeeper from the Italian club.
The Brazilian has already saved a number of points for the Reds this season, but his efforts on Tuesday may have been his most important yet.
Alisson came up with a late-game save on Arkadiusz Milik to preserve Liverpool's 1-0 win as the Reds advanced to the Champions League last 16 .
The game-saving moment earned the goalkeeper the plaudits of former Manchester United star Ferdinand, who gave Alisson full credit for his contributions so far this season.
"You buy a player like that. He's done nothing really the whole game," Ferdinand said on BT Sport .
"He wasn't really called upon. Distribution was fine, but in terms of making saves, he wasn't.
"Then, all of a sudden, that one save, when that moment in the game comes, great goalkeepers step up, and he's proven to be a fantastic addition."
Former Reds winger Garcia was also full of praise for the Brazilian star, who has certainly provided an upgrade over the likes of Loris Karius and Simon Mignolet.
"It's not about being disrespectful, it's about facts," Garcia said when asked about the upgrade.
"Those kind of moments are the key moments when you need to stand still, to hold it, to be confident, and Alisson proved it not only today, but he has the whole season."
With the win, Liverpool finished second in their group behind Paris Saint-Germain, who took down Red Star Belgrade in their own match on Tuesday .
The Reds face Manchester United on Sunday in the club's return to Premier League action.