Mets closer Edwin Díaz took offense when A's reliever Austin Adams used the Mets' signature 'OMG' celebration during a game.
Díaz felt that Adams crossed a line by mimicking the celebration, which is typically reserved for Mets players after scoring home runs.
Adams explained that he wasn't intentionally copying the Mets, but rather celebrating his own success in a tricky situation.
The rivalry between the two teams is likely to escalate, with both teams looking for opportunities to get one over on each other in the upcoming games.