David Luiz has vowed "to fight almost to the death" to help Chelsea overcome former club Benfica in the Champions League quarter-finals.
Luiz, who spent four years with the Portuguese giants before joining the Blues in a £26.5million deal in January last year, was looking forward to catching up with some old friends ahead of Tuesday night's first leg in Lisbon.
But the Brazilian insisted any loyalties to the club that brought him to Europe would end the moment combat began at the Estadio da Luz.
"They'll be my mates right up to the first whistle but, after that, Benfica and Chelsea are going to be adversaries and both are going to fight almost to the death to win," vowed Luiz.
"As the ref starts the game, the fight will start.
"Everybody knows I love Benfica and respect Benfica but I won't make it easy for them.
"I'm not going to leave them any space to win.
"I'm happy to be here. It's very special to be here.
"I had a great time here, from my first day in this room being presented as a Benfica player to the day I left.
"I'm glad to be back, and to be received so well. I'm happy to be playing against such a significant team."
Luiz has come under-fire for some of his performances this season, but the central defender believes he had improved as a player and as a person since leaving Portugal.
"I'm older and wiser, more experienced from all the games I've played so far, and I have more responsibility," he said.
"I've played more, and am getting older."