Scottish football saw a major controversy over VAR in the second game in use of the system when Celtic scored a seven-goal thriller at Tynecastle.
Hearts replacement Lawrence Shankland scored a hat-trick but was overshadowed by Premiership leaders, who secured a 4-3 win thanks to 76-minute winner Greg Taylor.
James Forrest, Giorgos Giakoumakis and Daizen Maeda also scored when the lead changed hands several times.
A pulsating game was also clouded by some hotly debated decisions involving newly introduced video technology.
The decisions were confirmed by VAR controls during St Johnstone’s win over Hibernian on Friday, but the first intervention came in the first stoppage time in Edinburgh when referee Nick Walsh was told to look at Cameron Carter’s challenge again. Vickers on Cammy Devlin from video assistant Steven McLean.
Walsh went to his monitor to watch the footage which clearly showed Devlin had caught the ball before he landed. Shankland scored from the spot for 1-1.
Moments later Celtic appealed for a penalty when the ball hit Michael Smith’s arm in the area after being lifted by Forrest. Walsh played again, and after a much shorter delay while McLean checked the footage, the game continued.
Smith seemed to be moving his arm towards the ball and Celtic manager Ange Postecolgou couldn’t believe the decision, laughing and clapping his hands sarcastically.
There was a controversial decision earlier when Anthony Ralston put the ball into the Hearts net, confirmed by the VAR, and the official video ordered a repeat of the home team’s second penalty of the day.
The tone of the game was set early on. Barrie McKay saw a first try saved by Joe Hart and Maeda went off target by a similar opportunity.
Celtic left-back Alexandro Bernabei gave the ball away on several occasions and one moment resulted in Robert Snodgrass waltzing through Celtic’s defense only for Hart who came out and denied it.
Celtic went straight to the park and scored an opening goal in the 14th minute. Ralston exploded on Reo Hatate’s inside pass and pushed the ball into the goal from the back line. Craig Gordon looked like he would have picked up if Orestis Kiomourtzoglou hadn’t slipped in to attempt to clear, and the ball turned for Forrest to nod home.
The first significant delay to the proceedings came after Walsh blew a free-kick at Hearts just before Ralston dove in to head a free-kick from Aaron Mooy. Eventually Gordon was cleared to take the free-kick from Walsh even though it looked like there was nothing wrong when Giakoumakis collided with Kiomourtzoglou.
Hearts striker Stephen Humphrys was causing problems at Celtic and threatened with two shots before going injured in the 39th minute. Shankland walked over.
Action continued at both ends. Hatate was unable to control the ball after being played following a very good Celtic move and Kiomourtzoglou headed just wide.
Shankland equalized from the spot with three minutes remaining and the drama continued after Celtic’s penalty was dismissed.
The former Dundee United striker put the hosts ahead 90 seconds after the restart when he shot home a low cross from Ginnelly from close range.
The action was relentless. Mooy missed a sitter and Devlin cut to the side before Forrest had a saved shot. Giakoumakis equalized when he headed home for Mooy’s corner in the 55th minute.
Celtic were leading four minutes later when Maeda scored a goal after Gordon webbed Mooy’s 22-yard shot.
Walsh gave Hearts the second penalty right after Devlin beat Moritz Jenz on a cross. After a check, Shankland saw his effort saved by Hart and missed his sequel, but Ginnelly ran home to knock home.
VAR officer McLean ordered a take back after the winger and Jenz were shown to invade. Shankland used a second chance to score his hat-trick by sending Hart in the wrong direction in the 65th minute.
Postecglou immediately dispatched Sead Haksabanovic, Liel Abada and Taylor and the latter two teamed up to put Celtic back in the lead. The left-back breaks into the small area to stab Abada’s deflected shot at home.
Abada was denied by Gordon and then the offside flag when Celtic saw the dramatic win with no more fears.