Manchester United have found themselves at the centre of a Champions League draw controversy.
The Red Devils booked their place in the last-16 of the showpiece competition by beating Villarreal to the top spot of Group F.
The draw for the first set of knockout fixtures in Nyon, Switzerland saw Arsenal legend Andrey Arshavin draw United to face Villarreal in the last-16.
But that was a mistake as two sides from the same group are not allowed to face each other.
As a result, another name was drawn out to face Villarreal - namely, Manchester City.
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However, when Atletico Madrid were drawn out for the next tie, organisers did not place Manchester United in the pot of potential opponents.
Video footage shows that no ball from United's pot - back row, second from the right - was included, whilst a ball from Liverpool was also mistakenly put into the mix.
Having both been in the same group, Liverpool should not have been able to take on Diego Simeone's side again.
"For Atletico Madrid, the possibilities are all except Liverpool, who were in the same group and Manchester United," explained host Giorgio Marchetti.
"Manchester United have already been drawn," Marchotti added, despite the fact their original draw had been a mistake.
UEFA are now assessing whether they must perform the Champions League last-16 draw all over again after the major mistake.
A senior UEFA source has told Mirror Football they are looking into the episode and whether the draw must be performed again, to preserve the integrity of the competition.
The episode has left Manchester United with a tough tie against star-studded Paris Saint-Germain, whilst a clash with Atletico Madrid, which ended up being impossible as a result of the error, would have been a preferable outcome.
"I don't think it's a foregone conclusion," said Michael Owen on BT Sport about United vs PSG. "In two months time, it could be a really close game."
"It'll be high intensity vs low intensity," declared Owen Hargreaves. "If they keep clean sheets, Ronaldo will score goals, you can guarantee that."
"I think they'll get better as the season goes on and they'll go close," said Joe Cole. "I think they'll beat Manchester United. It'll be a big one for [Mauricio] Pochettino. If you're a top manager, at that club, you've got to win tournaments like this."