First-half goals from Rob Hulse and Robbie Blake helped Leeds beat Southampton to claim their third win in four games.
Hulse gave his side the lead after only four minutes, heading home Gary Kelly's pinpoint cross.
He turned provider for the second on 19 minutes, laying the ball off to Blake who curled in a 20-yard shot.
Teenager Theo Walcott gave Southampton some hope with a strike six minutes later but an equaliser never arrived.
Leeds head coach John Carver on Robbie Blake:
"To be honest, it was a scruffy performance, but we've ground it out and got the three points.
"I'm delighted for Robbie Blake because he's been working so hard in training.
"He's been disappointed with his performances so far but he did well on
Saturday and again here. He deserved his goal and what a goal it was."
Southampton boss Harry Redknapp:
"We will win more than we lose and you don't have to be Einstein to see that - I'm confident we'll go up.
"I've seen everything in this league and I don't think there is anyone better than us.
"I'm not saying we're going to finish top, but I think we'll go up."
Leeds: Sullivan, Kelly, Butler, Gregan (Kilgallon 56), Harding,
Richardson (Einarsson 75), Douglas, Derry, Lewis,
Blake (Healy 65), Hulse.
Subs Not Used: Bennett, Moore.
Booked: Derry, Douglas.
Goals: Hulse 11, Blake 19.
Southampton: Niemi, Cranie, Hajto (Delap 83), Lundekvam,
Higginbotham, Belmadi (Kosowski 68), Oakley, Quashie, McCann,
Fuller (Jones 75), Walcott.
Subs Not Used: Ormerod, Smith.
Booked: Belmadi, Oakley.
Goals: Walcott 25.
Ref: M Jones (Cheshire).