Arkadiusz Milik looked to have won the game with a 94th minute header from a corner, but VAR disallowed the goal after the ball took a slight nick off Leonardo Bonucci, who was stood in an offside position.
Bonucci had levelled the match just a minute previously with a rebound from his own missed penalty, as Juventus came back from a 2-0 half-time deficit to earn a point.
In addition to Milik's goal being ruled out, the striker was given a second yellow card for his overzealous celebration. A scuffle ensued which saw Juve's Juan Cuadrado and Salernitana's Federico Fazio given straight reds, while Allegri also received his marching orders for his part in the altercation.
Allegri spoke on his VAR frustrations after the game, saying: "I can't give interpretations because I'm not a referee, you have to accept the decisions. I think the referee was good.
🤯🤯CAN YOU BELIEVE IT!! Arkadiusz Milik thought he had the winner for @juventusfcen DEEP in stoppage time, but it was ruled out by #VAR then chaos ensued in this manic clash with @OfficialUSS1919— beIN SPORTS (@beINSPORTS_AUS) September 11, 2022
📺MATCH HIGHLIGHTS 👉 https://t.co/ckdBoeEuAp #SerieA #JuveSalernitana #JUVSAL pic.twitter.com/Os4RyYNyPC
"On the goal I would like to see the image where you can see [Antonio] Candreva who is in front of the ball where the corner is taken. I would like to know if there is an image where Candreva is seen.
"Since the beginning of the season we are a bit unlucky with this VAR, we can say this."
Allegri, in his second spell as Juve head coach, was disappointed with his team's first-half reaction to going a goal behind through former Bianconeri wide-man Antonio Candreva, before Krzysztof Piatek doubled the visitors' lead just before the break.
"Let's analyse the game. We played 20 minutes very well, then after the goal we stopped," Allegri added.
"Sooner or later it had to happen to go behind, I wanted to see the reaction. It was the first time we were at a disadvantage and my curiosity was to see how we would react. We didn't react well.
"Then in the second half we played a good match. Salernitana played a good game and I have to congratulate [Davide] Nicola."