Cesar Azpilicueta appeared to clash with Chelsea fans at Stamford Bridge on Wednesday after a 4-2 home defeat to Arsenal in the Premier League.
The defender was caught on camera approaching the stands and gesturing at a clustre of supporters in the immediate aftermath of the game.
The Blues were hosting Arsenal at limited capacity due to sanctions on owner Roman Abramovich.
Watch: Azpilicueta appears to clash with Chelsea fans
What was said about the incident?
"I was not part of [the moment]," said Blues manager Thomas Tuchel. "I saw it, but honestly I can understand the fan."
Anger at Saka penalty decision
Azpilicueta also expressed frustration in stoppage time when his physical duel with Gunners forward Bukayo Saka in the box was deemed a foul.
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Saka converted his penalty to give Arsenal a fourth goal on the night.
"Of course he is going to be angry with me but it is what it is," Saka said after the match to Sky Sports. "It was a penalty."