An 86th minute blunder by Lyon keeper Anthony Lopes handed Benfica a late goal for a 2-1 victory on Wednesday that threw Champions League Group G wide open.
Pizzi scored the winner after Lopes inexplicably threw the ball straight into the player's path who had no problem firing in from 25 metres for their first win in this season's competition.
Rafa Silva had grabbed a fourth minute lead for the hosts but his injury a little later deprived Benfica of their main attacking threat.
There was little in terms of attacks from the visitors, under new coach Rudi Garcia, until Memphis Depay volleyed in the equaliser at the far post in the 70th. Benfica hit the post in the 85th but were gifted the winner by Lopes a little later.
Benfica climb to three points, one behind Lyon and Zenit St Petersburg. RB Leipzig, who beat Zenit 2-1 earlier on Wednesday, are top on six points.
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TV channel and live stream information
The match will be televised live on BT Sport Extrra 5 and can be streamed live online via the BT app and website, with kick-off scheduled for 8:00pm BST.
You can follow all the action and analysis on Standard Sport's LIVE blog.
Lineups
Benfica: Vlachodimos, Tomas Tavares, Dias, Ferro, Grimaldo, Fernandes, Florentino, Pires, Rafa Silva, Seferovic, Cervi
Subs: De Tomas, Pizzi, Jardel, Andre Almeida, Taarabt, Zlobin, Vinicius
Lyon: Lopes, Dubois, Denayer, Marcelo, Kone, Terrier, Aouar, Tousart, Cornet, Dembele, Depay
Subs: Andersen, Da Silva, Traore, Thiago Mendes, Reine-Adelaide, Tete, Tatarusanu
Referee: Ivan Kruzliak (Slovakia)
