Mauricio Pellegrino has admitted he will always be grateful to Rafael Benitez, but has vowed to get one over his former manager on Sunday.
Pellegrino played under Benitez at Valencia and then Liverpool before working as a first-team coach alongside the Spaniard at Anfield and also Inter Milan.
But the 46-year-old Argentine, who replaced Claude Puel at Southampton over the summer, will be thrust against his ex-boss for the first time in his managerial career when Newcastle travel to St Mary's Stadium on Sunday.
"First of all, Rafa was a really important team-mate because we were working together at Valencia as a player and then at Liverpool," Pellegrino said.
"He gave me the opportunity to work in professional football as his assistant and to be in contact with the Premier League and with this wonderful team.
"My experience was really nice. I will always be grateful with Rafa, not just on the professional side, but he is a good example to me as a person, too.
"I am now in a situation where I play against him, because I am part of the Premier League, but I have to be ready to prepare my team and I will try to beat them."
Southampton host Newcastle following a troubled start to the new campaign in which Pellegrino's defensive style has courted criticism from some sections of the St Mary's support.
The Saints have failed to score in four of their opening seven league fixtures, but Pellegrino, who managed Valencia for six months and more recently Alaves, insists he will not change his philosophy.
"I will train and do the things that I believe in," Pellegrino added. "As a manager you can control the training session and your style, and sometimes you cannot control the result and this is part of the job.
"I have had to be honest with my players, and we have had to improve on a lot of things but we have to keep going and keep doing the positive things that we have done in the past few games."
Southampton suffered back-to-back defeats - at home to Manchester United and then away at Stoke - before the international break, and Pellegrino has described Sunday's fixture against Newcastle as a must-win for his side.
"It will be important for us to win because we need the three points," said Pellegrino, who will have forward Shane Long available for selection after he missed Ireland's World Cup qualifier against Wales with a hip injury.
"We need to get a result because we deserved more from the last two matches especially. We played better than Stoke and we did not deserve to lose against Manchester United at home, so the game on Sunday will be important for us."