Three second-half goals at Hillsborough boosted Sheffield Wednesday’s play-off push but increased Charlton’s problems.
After concerted pressure, Tom Lees broke the deadlock with a close-range header, then Fernando Forestieri turned in a rebound off the post.
The win was sealed as Charlton’s El-Hadji Ba was unlucky to turn Alex Lopez’s shot into his own net.
Wednesday stay sixth in the Championship, with the Addicks six points from safety at the other end.
After losing to neighbours Rotherham in their last home game, the Owls were determined to avoid another slip-up and piled on the pressure from the start.
Visiting keeper Nick Pope was swiftly called into action to keep out Forestieri’s looping header, but Charlton put up a resolute defensive effort after that to keep the first half scoreless.
The interval introduction of Atdhe Nuhiu and Lopez gave Wednesday more threat up front. Forestieri drew another good save from Pope, before Nuhiu and Jack Hunt went close.
But once the dam was finally broken by Lees’ header, Charlton crumbled, with Forestieri soon adding a second after Nuhiu headed against the post.
The third goal, an unlucky deflection, just rubbed salt into the wounds for the Addicks, who had lifted their spirits with a welcome home win over Middlesbrough in their previous game.
Sheffield Wednesday boss Carlos Carvalhal: “The team for moments in the first half lacked confidence but never lost control or organisation.
“We knew Charlton couldn’t press all the time and when we had more time and space we started playing very well.
“When they lost energy we played better and we had a very good second half at a very good level. We deserved the win and the scoreline.
“We are the second or third best attack in the division and I am very happy about this because we promised our fans good attacking football and we are delivering it.”
Charlton boss Jose Riga: “It’s a disappointment because we’re coming through three good games.
“We knew everybody had to be at their best level, the level we had against Middlesbrough and we didn’t have that today.
“We were present in most of the game, we couldn’t find a way to compete in the final 20 minutes.
“We have to work and try to find the right solutions. I don’t accept the situation, not at all.”