Grzegorz Rasiak is targeting scoring his 20th goal of the season against his old club at St Mary's on Saturday.
The Polish striker made his name in English football at Derby after being signed there during George Burley's time at Pride Park.
He is still fond of the club but would love his 20th of the season to come against them and close the gap between Saints and the league leaders to just four points.
He said: "Now we have a very big test because we are playing against the team in first.
"It will be a very big game for us because we are seven points behind Derby and we want to be just four after this weekend.
"The gap between us and second is just one point but we know Birmingham have two games in hand so this is a massive game for us.
"We would like to win the game at St Mary's."
Rasiak could have a new strike partner with Marek Saganowski in the squad, though Kenwyne Jones' injury is not as bad as first feared.
He added: "I'm absolutely not surprised to see them top.
"I'd like to see Southampton in first position and Derby in second because that is the best for me.
"They've got very good players and seven new players signed in January and a new manager so we'll see.
"They play very solid the last five games with a lot of 1-0 results so we will try and score and win the game.
"I think the fans liked me when I played for the team and always I respected them and they respected me but it's football and when I play for the opposition for 90 minutes I am against them.
"Hopefully it will be OK but at St Mary's my supporters will be more than Derby supporters."
Don't miss tomorrow's Daily Echo for Rasiak's opinions on Saganowski and five pages of Saints v Derby preview as well as George Burley's exclusive Echo column.
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