Enzo Maresca has questioned the consistency of Premier League officiating after Moisés Caicedo was sent off in Chelsea's 1-1 draw with Arsenal on Sunday.
Caicedo was dismissed by referee Anthony Taylor after a VAR review for a late challenge on Mikel Merino seven minutes before half-time at Stamford Bridge.
Despite being reduced to 10 men, Trevoh Chalobah opened the scoring on 48 minutes before Merino equalised just before the hour mark.
Although Maresca had no complaints with Caicedo's sending off, the Blues boss believes Piero Hincapié should also have been dismissed for elbowing Chalobah while also referencing Rodrigo Bentancur's yellow card for a late tackle on Reece James during their win at Tottenham on Nov. 1.
James claimed Hincapie was fortunate not to be sent off and Maresca, whose Chelsea side have picked up seven red cards already this season, said: "I think Reece is right but... they ask me about Moi's [Caicedo] red card. It is a red card. But why Bentancur on Reece is not a red card [against] Spurs away?
"So us, as managers, we struggle to understand why they judge in different ways. Moi it is a red card, yes. Bentancur is a red card, yes. Why they not give them red card? It is just that we struggle to understand.
"The reality is that is a red card. But why they judge in different ways? And the Trevoh one, I ask the referee. He said to me it was not an elbow. He has a black eye, he was with ice at half-time but they judge in different ways."
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Gunners boss Mikel Arteta accused Chelsea of "constantly targeting" his players on a yellow card in a bid to even up the game after Caicedo's dismissal.
Arsenal had four players booked in the first half: Martín Zubimendi, Cristhian Mosquera, Riccardo Calafiori and Hincapie.
Arteta took off Calafiori at half-time for Myles Lewis-Skelly, who was booked nine minutes after the restart.
"After the sending off of Caicedo, we wanted to settle the game," said Arteta.
"We didn't manage to do that. We had four yellow cards. Obviously those players were constantly targeted to try and even the game in terms of numbers. At half-time, we said 'OK, let's pause it now.'"