Match ends, Sheffield United 2, Charlton Athletic 0.
Two goals in three second-half minutes from Ryan Flynn and John Brayford took League One Sheffield United to a Wembley FA Cup semi-final.
Nigel Clough's side became the first third-tier side to reach the last four since Wycombe Wanderers in 2001.
After Callum Harriott had missed from seven yards for Championship side Charlton, midfielder Flynn stretched to poke in Jose Baxter's bouncing cross.
Full-back Brayford quickly added a second with a 25-yard deflected shot.
The victory was United's ninth in a row in all competitions, and means a first FA Cup semi-final since 2003 for the Blades.
Clough's team have become the big story of this season's competition, having already knocked out two Premier League sides - Aston Villa and Fulham - plus Championship side Nottingham Forest on their run to the quarter-finals.
In front of a sell-out crowd at Bramall Lane, there were few chances during a first half in which the tension appeared to get to both sets of players.
Charlton striker Marcus Tudgay's deflected shot, turned aside by home keeper Mark Howard after half an hour, was the first effort on goal of any note.
At the other end, United's on-loan Liverpool midfielder Conor Coady had a goal ruled out for offside, and defender Bob Harris drove a shot just over, having been set up by Harry Maguire.
Centre-back Maguire's shot on the turn hit the side netting early in the second half, before Harriott passed up a great chance to fire Charlton towards their first FA Cup semi-final since they last won the trophy in 1947.
Tudgay cut the ball back from the by-line, but Harriott turned his shot wide on the stretch from seven yards.
The Blades then took advantage of that miss to score twice in quick succession, with Flynn turning in the opening goal from six yards with the sole of his boot after Baxter's cross from the left unstitched the Charlton defence.
Almost straight away, the lead was doubled as full-back Brayford's low shot from outside the penalty area was deflected past keeper Ben Hamer.
Coady thought he had added a third from close range as the ball rebounded to him off a post, but was again ruled offside.
Blades keeper Howard turned away a late shot from Charlton's Iran international substitute Reza Ghoochannejhad late on, but the visitors failed to mount a comeback.
Sheffield United boss Nigel Clough:
"We were nervous in the first 20 minutes and it was important to get in 0-0 at half-time.
"The atmosphere, it saps you when you're not used to it and a lot of players playing in this sort of thing for the first time, this atmosphere takes your energy and it takes your breath away at times.
"To get to this stage as a League One club in the semi-final is an incredible achievement."
Charlton boss Chris Powell:
"Obviously there was the opportunity to go to Wembley and credit to Sheffield United.
"We had the chance to break the deadlock. Really that's the game-changer for me because they then went 1-0 up and a deflected second goal and that's two in two minutes.
"That left us with a big mountain to climb and sadly we couldn't get enough flowing to get ourselves back into it."
- 7FlynnBooked at 14minsSubstituted forMcGinnat 90'minutes
- 11BaxterBooked at 80minsSubstituted forDaviesat 81'minutes
- 21ScougallSubstituted forPorterat 86'minutes
- 23WilsonSubstituted forGhoochanneijhadat 71'minutes
- 39PoyetSubstituted forGreenat 71'minutes
- 4JacksonBooked at 39mins
- 9ChurchSubstituted forAjdarevicat 65'minutes
- 11HarriottBooked at 71mins
- Lee Mason
- Shots on Target
Second Half ends, Sheffield United 2, Charlton Athletic 0.
Corner, Charlton Athletic. Conceded by Mark Howard.
Attempt saved. Reza Ghoochanneijhad (Charlton Athletic) left footed shot from the centre of the box is saved in the top centre of the goal. Assisted by Rhoys Wiggins.
Attempt blocked. Astrit Ajdarevic (Charlton Athletic) left footed shot from outside the box is blocked. Assisted by Rhoys Wiggins.
Foul by Richard Wood (Charlton Athletic).
Harry Maguire (Sheffield United) wins a free kick in the defensive half.
Substitution, Sheffield United. Stephen McGinn replaces Ryan Flynn.
Foul by Reza Ghoochanneijhad (Charlton Athletic).
Ben Davies (Sheffield United) wins a free kick in the defensive half.
Offside, Sheffield United. Jamie Murphy tries a through ball, but Chris Porter is caught offside.
Substitution, Sheffield United. Chris Porter replaces Stefan Scougall.
Attempt blocked. Ryan Flynn (Sheffield United) left footed shot from the right side of the box is blocked. Assisted by Stefan Scougall.
Callum Harriott (Charlton Athletic) wins a free kick on the left wing.
Foul by Ryan Flynn (Sheffield United).
Substitution, Sheffield United. Ben Davies replaces Jose Baxter.
Jose Baxter (Sheffield United) is shown the yellow card for a bad foul.
Danny Green (Charlton Athletic) wins a free kick in the defensive half.
Foul by Jose Baxter (Sheffield United).
Corner, Charlton Athletic. Conceded by Robert Harris.