Maurizio Sarri feels referee Craig Pawson is "not up to officiating in Europe" after being left angry at the English referee's display in Lazio's 1-0 win against CFR Cluj.
Pawson sent off Lazio defender Patric 15 minutes into Thursday's Europa Conference League knockout round play-off first leg for a challenge on Ermal Krasniqi.
Patric was issued a straight red card for preventing a clear goalscoring opportunity, despite being around 15 yards from the penalty area with other Lazio players around him.
Lazio played the remainder of the match with 10 men, but they found a winner through a Ciro Immobile goal on the brink of half-time at Stadio Olimpico.
Sarri was furious with the decision to send off Patric, however, with the centre-back subsequently ruled out of next week's return leg in Romania.
"We're unfortunate that a referee not up to officiating in Europe has taken charge," Sarri told DAZN. "He's absolutely unsuitable.
"He changed the match by showing the red card for a foul that wasn't a clear opportunity to score a goal. He then continued to show some strange yellow cards.
"But on a night when everything seemed to be going in the wrong direction, we still obtained an acceptable result."
Pawson, who has officiated international and European fixtures since 2015, has issued 59 yellows and zero red cards in 14 Premier League games this season.
The 43-year-old's next assignment is as fourth official for Liverpool's trip to Newcastle United on Saturday.