Porto manager Sergio Conceicao claims to have been insulted by Chelsea boss Thomas Tuchel after two sides clashed in Sevilla.
The Blues progressed to the semi-finals of the Champions League on Tuesday night despite losing 1-0 to the Portuguese side on the night.
Chelsea progressed 2-1 on aggregate, despite Porto winning the second leg through an incredible 93rd-minute overhead kick from Mehdi Taremi.
The majority of the game was dull to watch to say the least, with 34 fouls between the two sides.
The gritty nature of the game spilled over after the final whistle, however, as the two managers were seen in an awkward exchange at full-time.
Tuchel congratulated his coaching staff before walking over to meet Conceicao, but the two barely fist-bumped before awkwardness ensued.
Conceicao looked to be shouting at Tuchel, and seemed to be upset at something he had said.
And speaking afterwards, the Porto boss revealed he had complained to the referee about his counterpart.
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"I was insulted by this man who is next door [Tuchel]," he said.
"I was telling the referee that the fourth referee heard those insults. That's all."
Tuchel didn't properly respond when asked about the incident afterwards.
He simply stated: "No harm done," when asked in his press conference.
Chelsea will now take on either Liverpool or Real Madrid in the semi-finals, with the two set to meet in the second leg of their last-eight tie on Wednesday night.
Madrid take a 3-1 lead into the reverse leg, and Liverpool have a mountain to climb in order to set up an all-english semi-final.