The Magpies have won five of their last six Premier League games and face a Saints side that has not won away from home in the league since September.
Yohan Cabaye scored the only goal of the game as the northeast side beat United at Old Trafford for the first time since 1972. Newcastle has now won five of its last six Premier League games and will be striving for a fourth consecutive win at St. James’ Park when Southampton makes the long journey north.
Pardew was sacked by Southampton when the club was in League One three years ago and the 52-year-old is expecting a stern test against his former employers.
He said: "We’ve had a really strong period and it’s important we focus on this game. There is a huge significance in this result. Southampton are a good side, very similar to ourselves in that they are set up to attack. It should be a cracker. We didn’t slip up against Norwich and West Brom and this is a game we’re really looking forward to."
France midfielder Cabaye will not feature against Mauricio Pochettino's side after picking up his fifth booking of the season against United. Mathieu Debuchy has recovered from a leg injury sustained at Old Trafford, so Ryan Taylor (knee) is the club's only other absentee.
St. James' Park has not been a happy hunting ground for Southampton, as it has not won there since 1997. Newcastle has won nine of its last 10 home games against Southampton and Pochettino's men have failed to win on the road since their 1-0 victory at Liverpool in September.
But the Saints managed to stop the skid with a 1-1 draw against Manchester City last weekend as Dani Osvaldo scored his second goal in as many games, and they will replace Newcastle in seventh place with a win on Saturday.
Pochettino said: "Newcastle are a team who have - in the last few weeks - been playing well. They are a physical, strong, aggressive side who are tough to beat. We are aware what we're up against."
Pochettino revealed Morgan Schneiderlin (groin) could play some part but the midfielder is not fit enough to play the whole game.
Nathaniel Clyne (hamstring), Victor Wanyama (leg), Artur Boruc (hand), Kelvin Davis (back), Danny Fox (hamstring) and Guly Do Prado (knee) are definitely out.