Gabriel's red card was later rescinded, but the defender was given a one-match suspension for failing to leave the pitch immediately, while Costa was slapped with a three-match ban.
"The thing is, I'm a very calm guy, but when I enter the pitch it's something different," Gabriel told British media.
"We are a little transformed. But it was just the heat of the moment, and a moment of learning too."
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"I learned a lot from it. I've caused problems to my team, but I know I've made a mistake. This whole thing is behind me now and it will never happen again. Now we must move on. It's in the past. I don't hate anyone and he (Costa) knows that."
Arsenal, who are third in the Premier League, will host 16th placed Crystal Palace at the Emirates Stadium on Sunday.
(Reporting by Shravanth Vijayakumar in Bengaluru; editing by Amlan Chakraborty)
