The Valencia defender said he was ashamed by his behaviour after running on to the pitch and punching Inter midfielder Nicolas Burdisso in the face, breaking his nose, before being chased by Milan players at the end of Tuesday's match.
Navarro and his team mate Carlos Marchena, who had kicked out at Burdisso helping trigger the pandemonium that followed, have been charged by UEFA with gross unsporting conduct along with Burdisso and his Inter team mates Ivan Cordoba and Maicon.
"I've never behaved this way before and I'm sure my family will be very disappointed in me," Navarro was quoted as saying in sports daily Marca on Wednesday.
"I'm ashamed and very much regret what I did. I haven't seen the television pictures and the truth is I don't want to either. I'm upset because I've never done anything like this in my life before nor will I again."
European soccer's governing body UEFA said both clubs face an investigation with the case now due to be considered by its control and disciplinary body on March 14.
The first knockout round match ended in a goalless draw, which meant Valencia qualified for the quarter-finals on the away goals rule after a 2-2 draw in Milan two weeks ago.
BURDISSO FLOORED
Tuesday's unseemly incidents flared up when Navarro sprinted off the bench at the end of the match as Marchena and fellow midfielder Burdisso squared up to each other.
Navarro floored Burdisso with a punch in the face and was pursued by several Inter players as he ran off the pitch. Inter coach Roberto Mancini said the Argentine's nose had been broken.
A mass brawl developed in the
Security guards intervened, but it took several minutes before the situation calmed down. Local media reported that Navarro left the stadium by a back door.
"When I saw that they were going for Carlos (Marchena) I ran on the pitch," said Navarro. "I saw Burdisso and was going to separate them, but I just lost my head.
"I expect to be punished. I very much regret what happened and I will accept whatever punishment I am given."
The defender added that he would try and ring Burdisso to apologise.
COWARDLY NAVARRO
Inter coach Roberto Mancini, who missed the incident at the time but watched replays, branded Burdisso's assailant a coward on Italy's Sky television network.
"I didn't see anything because I was going back to the changing rooms, but the lads told me what happened," he said.
"Looking at the pictures, one thing is certain, that the Valencia player is a coward. That's the only thing you can call a man who gives someone a punch like that and then runs away."
Inter president Massimo Moratti was far more diplomatic and said his club would not be seeking redress from UEFA.
"I'm sorry for the player (Burdisso) and for everything that happened at the end of the game. We really did't expect to have things like that happen any more."
As for reported trouble between opposing players in the dressing rooms, he said: "There wasn't a fight there. The UEFA delegate was aware of the situation and he's a good man.
"He'll do what he has to do. But I don't think there will be any action from Inter over this."
(Additional reporting by Mark Ledsom and Trevor Huggins)