The Black Cats have given up 18 points from winning positions this season and their lead was wiped out within three minutes of the restart.
Chris Mepham cheaply lost possession and Paterson headed home from Ingelsson's chipped cross for his 50th goal in English football, although he also had to go off injured soon after scoring.
The Owls would have completed a turnaround shortly after, but for a fine save from Anthony Patterson to deny Ingelsson.
Mayenda restored the visitors' lead when he powerfully headed home a beautiful ball over the top from Trai Hume to justify Le Bris' switch.
It was the teenager's sixth goal of the season, and a second double against Wednesday, having scored two in the 4-0 win at the Stadium of Light in August.
Sunderland saw this one out and will now hope for a favour before they host Cardiff City on Saturday, 8 March.
They still have that gap to make up on the Blades, with Burnley sandwiched between the two, three points ahead of the Black Cats. Both Sheffield United and Burnley are in action before Sunderland play again.
As for Wednesday, who have now lost all seven games against the Championship's top four this season, this was a fifth consecutive home game without a win which has stalled any momentum they may have wanted to build in search of a play-off spot.
Sheffield Wednesday head coach Danny Rohl told BBC Radio Sheffield:
"This game shows a bit of everything from the last few weeks, two big injuries in key moments, an easily conceded goal, a lot of missed opportunities and two moments where you do not get the right decision.
"At the moment it is really hard to take because I see how much my players invest.
"The first goal was bad, but the second goal was bad, bad, too easy. At the moment, we destroy our hard work with one single moment and this is hard for the team."
Sunderland head coach Regis Le Bris told BBC Radio Newcastle:
"It was important to give energy to the team, even if it wasn't easy to play football because the pitch was difficult for both teams.
"It was more a question of energy, commitment, connection with the team and resilience. Even during the game we conceded the equaliser and it was important to stay connected and to find a solution to score, so it's good news for us.
"Wilson did really well this season and is one of the best strikers in the league, for sure.
"But we need two or three strikers to be competitive in this league so maybe it was the right time for Wilson to recover a little bit and Eliezer was ready."