Charlton manager Chris Powell says his side cannot relax despite closing in on promotion to the Championship.
Back-to-back wins over the Easter weekend kept their lead at the top of League One at eight points.
Powell told BBC London 94.9: "It is about trying to see it across the line now. If you got 91 points in past seasons then you were up.
"But the two Sheffield teams are really pushing us and trying their best to get up there."
"For us to get three points from Oldham and follow it up with the performance against Walsall, I'm very pleased," he added.
"It is about results and winning ugly at times.
"For us to have another clean sheet and for players to really dig deep, they're a real credit to this football club.
"No-one's gained any ground on us and with four games to go, it's really pleasing."