Rafael Benitez will lock horns with old friend Mauricio Pellegrino on Sunday relishing a battle of wits with a man who knows him inside-out.
Newcastle boss Benitez was so impressed with his former Valencia defender that he appointed him as his assistant at both Liverpool and Inter Milan.
This weekend, the Spaniard will be in the away dug-out as his Argentinian counterpart sends his Southampton team into battle with the Magpies, and there will be few secrets between the two.
Benitez said: "He is someone who has always been focused and worked hard. He likes football and likes to study and learn.
"He knows everything about me because he was my player and assistant. He has an advantage, but at the same time we know him really well too. It is a special situation.
"If you wanted to say something or change something, he would know already. Players don't analyse the game, but when you are a coach, you know tactics and how people prepare for a game.
"He will have an advantage, but we will have that advantage too."
The Saints have won only once at St Mary's so far this season, and Newcastle will arrive hoping to build upon a run of only one defeat in their last five games, culminating in a creditable home draw with Liverpool before the international break.
They will do so with several members of their squad having returned from World Cup qualifying duty on a high - striker Aleksandar Mitrovic helped Serbia to reach next summer's finals while Rob Elliot and Ciaran Clark were in the Republic of Ireland squad which booked a play-off berth with victory in Wales.
Benitez said: "We have some of them that were quite happy, the Irish in particular - that is good. When you have so many around, some will be fine and some have to prepare for the next challenge.
"The main thing is they are focused on the weekend."
Jonjo Shelvey will be available despite breaking a finger trying to separate team-mates Jamaal Lascelles and Mohamed Diame during a training ground bust-up.
The midfielder is expected to play wearing a special cast to protect the injury.