Celtic manager Neil Lennon has described referee Alberto Undiano Mallenco's performance as "pro-Juventus" following his side's 3-0 defeat to the Italians.
Lennon insisted the Hoops were denied two clear penalties for grappling in the box as they were ruthlessly swept aside by Antonio Conte's men at Parkhead.
"I thought [the referee] was poor," he told reporters. "I thought he was very pro-Juventus. I was disappointed with his performance to say the least."
"I'd like to ask the referee: 'Is the game different in Spain and Italy?'" the Northern Irishman also told ITV.
"Every time one of my players was moving or trying to lose his man he was fouled, time and time again. He should have given a penalty on at least two occasions for us."
The 41-year-old went on to claim his side deserved more, and lamented the performance of defender Efe Ambrose upon his return from a victorious Africa Cup of Nations campaign with Nigeria.
He added: "I think the scoreline flatters Juventus. I thought for the best part of the game 70 odd minutes up until the second goal we were by far the better side - but we can't give away the goals we gave away. It was sloppy.
"We took a gamble [on Ambrose], I thought he was poor for the first goal but we had a great opportunity to equalise and we had some great chances to be fair. We played ever so well for long periods of the game and we switched off defensively for the second goal and the third goal was poor.
Lennon also remained realistic about his side's chances of progression to the quarter-finals but insisted that his young players will learn from the defeat.
"We'll need a miracle. It’s the harsh reality of Champions League football," he admitted. "Some of our young players will have learnt a lot tonight."