Paul Lambert will always view Martin O'Neill as "the gaffer", but is all set to tackle his old boss head on at Sunderland tonight.
The Norwich City manager worked under the Northern Irishman at Celtic as the Glasgow giants enjoyed a hugely successful spell, reaching the 2003 Uefa Cup final, winning three Scottish Cups, the Scottish League Cup and the Scottish Premier League title three times, as well as playing in the Champions League.
O'Neill, 59, left Parkhead at the end of the 2004/05 season to care for his ill wife, but returned to the game at Aston Villa and, after another break, took over at Sunderland in December following Steve Bruce's departure.
Lambert has often been compared to his former manager, who like the Scotsman had spells in charge of Wycombe Wanderers and, albeit briefly, Norwich.
And the 42 year old feels if he can emulate O'Neill's achievements, it will be a job well done. "My five years at Celtic under him was a major part of my career and you learn a lot," Lambert said.
"He is brilliant at getting the best out of people, playing with confidence. I loved playing under him. It was terrific. Whenever I needed advice, I knew I could pick up the phone to him.
"I would never call him by his first name in case I get fined still. I have too much respect for him and what he has done.
"There was only one answer to what would happen when he took over at Sunderland, and it was he would take them up the league.
"You take bits from everybody you have worked under and I have always said if I could get a touch of the success he has had, then I will be doing all right."
Lambert added: "The gaffer will say himself it is not about me against him, it is Sunderland versus Norwich.
"I have to try to win for Norwich and he has to try to win for Sunderland, but it will be strange because of the relationship I have got with him."
Norwich head to the Stadium of Light on the back of an impressive six-match unbeaten run which has seen them consolidate ninth place in the Premier League and secure a place in the last 16 of the FA Cup with their victory at West Bromwich Albion.
"We are playing with a lot of confidence at the minute and it will be a great game against a really good side," Lambert said. "We will do everything we can to win and have a lot of confidence at the moment."
Wayne Bridge has gone straight into the Sunderland squad for the game after completing a loan move from Manchester City.
The 31-year-old full-back, who has not played a competitive game since September, is included in the midst of an injury crisis which has robbed O'Neill of defenders Wes Brown (medial ligament), Titus Bramble (Achilles/foot) and Matt Kilgallon (ankle).