Video technology caused controversy in Juventus's 2-0 win at Fiorentina on Friday.
Federico Bernardeschi scored against his old team before Gonzalo Higuain sealed victory as Juventus moved top of Serie A, two points above Napoli, which hosts third-place Lazio on Saturday.
But there was an incident in the first half that took center stage.
Fiorentina was awarded a penalty in the 18th minute after Giorgio Chiellini blocked Marco Benassi's cross with his arms.
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While Jordan Veretout waited to take the spotkick, the VAR (video assistant referee) was consulted. After a three-minute wait, a free kick was given to Juve because Benassi was offside.
The pass to the winger had come off Juve defender Alex Sandro but the VAR deemed he had simply deflected the ball.
"They took a lifetime to decide," said Fiorentina coach Stefano Pioli. "The explanation given to us was that the penalty was annulled because of offside.
"But I don't accept this decision: Alex Sandro made two touches, not just one, it's difficult to believe it wasn't voluntary.
"For me it wasn't offside. And then the referee took more than three minutes to decide, how is it possible that he didn't go to look at the replay himself?"
Fiorentina almost went ahead before the break when Gil Dias ran almost from halfway before unleashing a fierce shot that crashed off the post into the arms of goalkeeper Gianluigi Buffon, who was making his 500th Serie A appearance.
Fiorentina had Juve pinned back early in the second period but the visitors took the lead with a superb Bernardeschi free kick in the 56th minute.
The 23-year-old Italy international joined Juve last July after spending 10 years at Fiorentina and was jeered by the home fans when he was substituted 12 minutes from time.
Fiorentina came close to an equalizer several times but Juve doubled its tally in the 86th minute when Higuain was sent clear by Chiellini and the Argentina forward lifted the ball over goalkeeper Marco Sportiello.
The win will boost Juve as it prepares to host Tottenham on Tuesday in the first leg of the Champions League round of 16.
"I want to congratulate the lads because we're getting some positive numbers: 62 points (this season) and only one goal conceded in our past 16 matches," said Juve coach Massimiliano Allegri.
"Now we have to recover for the Champions League. It will be very hard, they are a very physical and skilful team and we will have to do well."