The game ended all square with Talal El Karkouri striking in the 59th minute after his 35 yard shot bounced off Michael Tonge and Matthew Kilgallon before slipping under a stretching Paddy Kenny arm.
But ten minutes later the Blades were back level when Jonthan Stead picked up the ball on the right hand side of the area before shooting into the far post to score after Nick Montgomery put him through.
Sheffield United manager Neil Warnock was pleased with his teams performance and pointed out that his team attempted to win the game.
"I think you could see we came to try to win the game and I thought we played some good stuff at times." Said Neil Warnock
"Charlton's opener was disappointing but my lads fought back really well and it was fabulous strike by Jon Stead. I think we deserved it.
"A lot of people didn't think we'd be where we are but we're right in amongst it, fighting for our lives."
Meanwhile Charlton Athletic manager Alan Pardew was happy with his teams performance but was disappointed in the way they went about there team after they took the lead.
Pardew said; "It was a tight, tense affair. Both sets of players carried the burden of trying to stay in the Premiership.
"I was happy with the way we played, but our goal actually affected us in a negative way more than it did them. We had our worst spell after we scored.
"But we're still right in there, so we fight on."