The video assistant referee played a major role, including ruling out an injury-time equaliser, as champions Juventus beat Sampdoria to keep up their unbeaten run in Serie A.
Riccardo Saponara thought he had taken a point, but the goal was ruled out.
Cristiano Ronaldo scored early on, and later put his side back in front with a penalty that was awarded for a handball which did not look deliberate.
Samp’s equaliser came from a penalty awarded after consultation with VAR.
Former Juve striker Fabio Quagliarella hammered home the spot-kick after referee Paolo Valeri took instruction from his assistant following Emre Can’s handball from a corner.
Elsewhere, 10-man AC Milan scored for the first time in five league games to complete a comeback victory over SPAL.
Andrea Petagna gave the struggling visitors a 13th-minute lead at the San Siro, but Samu Castillejo equalised three minutes later before Gonzalo Higuain completed the scoring in the second half.
Suso was dismissed for a second bookable offence late on, but Gennaro Gattuso’s side held on to move into fifth place in the table.
Three big decisions – but was VAR right?
Juve looked to be on their way to a routine victory when £99.8m summer signing Ronaldo drilled home after just 107 seconds, before VAR took centre stage.
32 minutes: Former Liverpool midfielder Can challenges Albin Ekdal at the near post from a corner and the ball hits him on the arm, which is above his head. Quagliarella scores from the spot.
Correct decision? Yes.
63 mins: As Juve push for a second goal, a corner is swung in by Miralem Pjanic. It hits Samp defender Alex Ferrari on the hand, which is by his side.
The referee has a chat with the VAR, decides to have a look at the pitchside monitor and still thinks it was deliberate. Ronaldo scores to make it 2-1.
Correct decision? No.
90+2 mins: In the six minutes of added time – some of which are down to the use of VAR – Saponara curls in a brilliant finish and rips off his shirt to celebrate. But the VAR tells the referee the substitute has come back from an offside position and rules out the goal.
Correct decision? Yes.
Play continued until the 99th minute, but Samp could not find a way through, so Juve go into the new year unbeaten in the league this season and having dropped just four points.
They could have won more comfortably, but Paulo Dybala and Blaise Matuidi both had efforts kept out by Sampdoria goalkeeper Emil Audero.