Former Southampton and Portsmouth midfielder Barry Horne says he is predicting a Saints victory in Saturday's south-coast derby.
Horne, 49, made 70 appearances for Pompey and 112 for Saints and played for both sides in the derby.
And the Welshman believes victory for Southampton on Saturday will all but seal their place in the Premier League.
"I think it will be a Saints win which will see them go on to win promotion," Horne told BBC Radio Solent.
He admits to having mixed emotions ahead of the weekend's game but believes the hosts need the points more than their south-coast rivals.
Saints lead the Championship by two points with six games to go while Pompey are five points from safety in the bottom three.
"I genuinely do have mixed feelings about Saturday," added Horne, who played for Saints between 1989-92.
"I would love Southampton to go up. They deserve to go up and have had an unbelievable season where you think they have come from and the little money they have spent in comparison to some teams in that league.
"They've been brilliant and seem to have got over that little wobble they had and I desperately want them to go up."
Horne, who played for Pompey between 1987-89, continued: "At the same time I would hate Portsmouth to go down.
"But I think it is more likely that Saints are going to go up than Portsmouth are going to stay up.
"So perhaps that just edges me to think I want Southampton to win because for Portsmouth to stay up they need to make up five points and have got a hell of a lot to do.
"I'm not saying they can't do it, I'm just saying I'm not sure they can."