Manchester City manager Pep Guardiola hit back at Sergio Conceicao after the Porto coach's claims he pressured referees.
Conceicao accused Guardiola of pressuring referees during Porto's 3-1 Champions League loss to City in October.
Ahead of the return Group C meeting on Tuesday, Guardiola denied the claims.
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"I'm not in agreement. He can say, maybe it's his opinion, but I'm not agreeing that we pressure the referees," Guardiola told a news conference.
"It's not the way that we in the history speak for ourselves. We are not the type of team to do this, honestly.