The Manchester City star was at the centre of the action after the full-time whistle of the Club World Cup final with Fluminense when getting involved in a scuffle with the Brazilian veteran.
At time it was unclear what had sparked the heated exchange, however Melo spoke out after the match to blame Jack Grealish for the altercation, saying: "When the game ended, Grealish went after Martinelli. He chose a little guy. He has no balls to face a big one.
"Grealish was passing close to Martinelli and I saw them talking, forehead to forehead, so I went after him. I pushed him. Walker pushed me, too. I went to defend a teammate."
The ex-Juventus star added: "I defended my institution. I will do this forever. No one will disrespect my institution or its athletes. No one will come and humiliate my friends or my club.
"I didn't want a mess. Grealish was disrespectful towards the Fluminense institution and I will never let that happen.
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"He was shouting 'ole' at the end of the game. This is something that the fans can do, not a player - an athlete on the field cannot be disrespectful.
"I went to defend Martinelli, who was being cornered by this athlete. And I would do it again. I am a warrior. Nobody can ever crow with a rooster."
Giving his version of events on X, formerly known as Twitter, Grealish said: "The 28-year-old said: ""Not once did I say 'ole'."
But Walker clearly saw the funny side of the incident as he shared some snaps of the altercation on Instagram.
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And ex-teammate Mahrez was willing to back Walker's chances too.
He replied with a laughing emoji: "My money on you don't disappoint me."
Such trouble won't have caused too many issues for Man City who will have been delighted to be crowned the top club side in world football following their 4-0 win in the final.
As a result, Pep Guardiola's side end 2023 with five trophies to their name including the Premier League, the FA Cup, the Champions League, the UEFA Super Cup and their latest piece of silverware, the Club World Cup.