Southampton boss Russell Martin says a win over Leeds in the Championship would be "a huge day" for the club.
Saints, currently 15th in the table, have lost their last four league games and been outscored 12-2 in the process.
United, who are 6th, are on a six-game unbeaten run and they haven't conceded a goal since the end of August.
"We are having a really tough time at the minute and we need to win," Southampton manager Russell Martin told BBC Radio Solent.
"But we're not going to go away and make drastic changes, we will tweak and adapt.