• Managers argue over penalty-box antics
• Uefa continue to consider performance of referee
Only an astonishing, second-leg comeback from Celtic would alter the discussion around their tie with Juventus.
The Italians left Glasgow with a 3-0 victory from the first leg three weeks ago but also having sparked fierce debate over their glaring, grappling tactics when defending corners. Celtic's ire over the approach of Juventus was so great that they took their complaints to Uefa, the European game's ruling body.
There is no sign of that discord abating. Indeed, on the eve of the return match, the Juventus manager, Antonio Conte, bit back at Neil Lennon, his Celtic counterpart.
"If Lennon complains about the referees perhaps he is a coach who can come [to] Italy because here we all complain," said Conte, with a smile. "Seriously, as a coach, Lennon is doing very well and achieving really great things. Celtic played really well in the first leg but if I'm going to analyse the game well, I can't just look at our game, but also theirs.
"I say that every time it starts, or there is a corner to Celtic, there is always punishment in favour of the defending team because there is a player who systematically blocks our goalkeeper in the six-yard box. In the case of the first leg, it was [Gary] Hooper.
"Regulation says that in the six-yard box a goalkeeper must not be touched and if he is it is systematically a foul. So I say every time there is a player that goes in there, then all angles systematically show there was a foul in favour of Juventus.
"He [Lennon] talks about the rules, so then I'll bring a dossier about the Celtic player blocking our goalkeeper. I repeat, we tried to gloss over these things. Maybe I'm being European and Lennon is being Italian."
Unsurprisingly, Lennon was unperturbed by Conte's sentiment. "Hooper is allowed to stand in front of [Gianluigi] Buffon," said the Celtic manager. "He [Conte] is talking rubbish. Any player can stand anywhere he likes in the box.
"He's not affecting the goalkeeper, he's not touching the goalkeeper and he's not preventing him from getting the ball. "If he prevents him from getting the ball then, yes, it's a free kick. But before the ball is kicked he's not doing anything and he is entitled to stand where he likes. So he is talking nonsense."
If anything, the Juve defence now has an even more forceful appearance since the return from injury of Giorgio Chiellini. "I watched Juve against Napoli the other night and Chiellini was all over [Edinson] Cavani," Lennon said. "He had him almost in a head lock at one point. There was a bit of afters and then Chiellini pulls his hair. You need to see it, honestly."
Lennon is still to receive an explanation from Uefa regarding the first-leg refereeing performance of Alberto Undiano Mallenco of Spain. Turkey's Firat Aydinus perhaps has the least enviable task – and the most scrutinised – of any in the Juventus Stadium evening.
"[Celtic's chief executive] Peter Lawwell said we will get a call from Uefa but we haven't had anything yet," Lennon added. "I am disappointed but is it really a surprise? We have a Turkish referee now – I don't know what Turkish referees are like but I hope he is stronger than the Spanish one.
"They are the top referees in their country so you expect them to be competent. I don't want to be trying to prejudice the game going into it.
"All I want is for him to do his job and I don't think Mallenco did his job properly in the first leg. I don't think I've seen it as blatant as that, ever. It was just so galling."
This sideshow is perhaps necessary, given the magnitude of Celtic's task against the Serie A champions and league leaders. Yet if, as expected, this is to mark the end of Celtic's admirable Champions League run then Lennon has urged his players to be "carried out on their shield".
The Northern Irishman explained: "It's an old saying my dad used to talk about. If you're going to go out, go out having given every last drop you've got.
"We can't go gung-ho. They are brilliantly well-organised defensively so we need to think our way around the game if we can.
"I'm not expecting to win the game three or four nil but I'd like to win it 1-0, 2-1 – if we could do that it would be a fantastic achievement again.
"Is the tie beyond us? I'm a realist. It will take a minor miracle but miracles do happen sometimes. We need to do it brick by brick, try to get a foothold in the game, try to take the lead, then can we get another one?
"We will need a lot of patience as well. A clean sheet is imperative. There are so many factors going into this game; even though a lot of people on the outside will say the tie is over, there is a lot still to play for – for us anyway."