After completing his stunning hat-trick to overturn the deficit in the round-of-16 tie, Ronaldo repeatedly thrust his hips in the direction of the crowd in celebration.
The ‘cojones’ celebration was thought to be a jibe at Atletico boss Diego Simeone, who celebrated in similar fashion after Atletico's first-leg victory.
In a statement, Uefa said: “Following a disciplinary investigation conducted by a UEFA Ethics and Disciplinary Inspector, in accordance with the Article 55 of the UEFA Disciplinary Regulations (DR), disciplinary proceedings have been opened following the UEFA Champions League round of 16 match between Juventus Football Club and Club Atlético de Madrid, played on 12 March in Italy.”
The Uefa Control, Ethics and Disciplinary Body will reach a verdict on what action is to be taken against the Portuguese talisman on March 21 at their next meeting.
However, Uefa chose to fine Simeone £18,000, rather than serve the manager with a touchline ban, meaning Juventus will expect the striker to receive a similar punishment.
After trailing Atletico 2-0 in the tie, Ronaldo spearheaded a famous victory for Max Allegri’s side in Turin, scoring twice with towering headers before converting a penalty in the game’s dying embers to send Juventus through to the quarter-finals.
The Italian champions, who lost their first game of the Serie A season on the weekend against Genoa, face Ajax in the next round after the Dutch side’s historic victory over Real Madrid.
The first-leg takes place at the Amsterdam Arena on April 10.
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