Swansea City made it two wins and two clean sheets from consecutive away games as Jamal Lowe and Jay Fulton found the net to secure just a second-ever victory at Hillsborough.
The south Yorkshire venue has not been a happy hunting ground historically for the Swans, but Lowe set them on their way to win number two from 18 visits as he slotted home his 12th goal of the season from Andre Ayew’s unselfish lay-off.
Freddie Woodman and Ryan Bennett made key defensive contributions for the visitors, and their efforts were rewarded when Fulton powered home a second-half header to seal the three points.
The victory, and a 20th clean sheet of the season, leaves the Swans on 75 points, seven behind second-placed Watford and nine points clear of seventh-placed Reading in the promotion picture.
And head coach Steve Cooper would have been pleased to see his side back up an important win at Millwall with another valuable points haul on their travels.
Swansea – unchanged from the weekend - were looking to pick up where they left off at Millwall, and Ayew came close to giving them a dream start in the fourth minute as he drove infield but sent his final effort just wide of the near post.
The Swans were having joy when they pressed Wednesday high, picking off the ball on a handful of occasions in the opening exchanges.
However, Wednesday began to settle with Adam Reach whipping in some threatening deliveries with his left foot.
Freddie Woodman punched away an effort from Josh Windass, and the Swansea keeper then made a magnificent save to prevent Liam Shaw firing home from Reach’s cut-back.
But it was the Swans who took the lead just past the half-hour mark through Lowe.
Ayew was the architect, chasing down defender Tom Lees to rob him off the ball and then laying on the finish for his fellow forward.
The Ghanaian wasn’t done, wriggling away from Julian Borner on the byline to head towards goal again, but he could not find the room to get away a cross or shot as blue and white shirts rapidly crowded him out.
The Swans retained the lead at the break, but needed Marc Guehi to cut out a dangerous Wednesday cross from the right in the early stages of the second half.
Ryan Bennett matched that effort a few minutes later, making a key block as Windass got set to fire at goal after cutting into the area.
However, Swansea were soon left frustrated when referee Matthew Donohue turned down penalty appeals as Kyle Naughton went down under a challenge from Borner.
And the visitors had a great chance to double their lead when Matt Grimes nodded the ball on to send Ayew towards the six-yard box.
Swansea’s top scorer lifted the ball away from the final defender, but keeper Keiren Westwood made the save from his low shot.
That started a better spell for Cooper’s side, but Bennett made another key intervention as he just got his head to a floating cross with Callum Paterson waiting to capitalise on any slip.
Swansea responded by putting the seal on the win with 17 minutes to go.
Connor Roberts, fresh onto the pitch as a substitute, produced a magnificent left-footed cross from Lowe’s pass, and Fulton was on hand to strongly head the ball into the net.
Sheffield Wednesday: Keiren Westwood; Sam Hutchinson, Tom Lees, Julian Borner (Andre Green 77); Liam Palmer, Joey Pelupessy, Barry Bannan (captain), Adam Reach; Liam Shaw (Izzy Brown 65), Jordan Rhodes (Callum Paterson 65), Josh Windass.
Unused Substitutes: Joe Wildsmith, Kadeem Harris, Matt Penney, Osaze Urhoghide, Alex Hunt, Elias Kachunga.
Swansea City: Freddie Woodman; Kyle Naughton, Ryan Bennett, Marc Guehi, Ryan Manning (Jake Bidwell 75); Jay Fulton, Matt Grimes (captain), Conor Hourihane (Korey Smith 80); Wayne Routledge (Connor Roberts 73), Andre Ayew, Jamal Lowe.
Unused Substitutes: Ben Hamer, Kieron Freeman, Joel Latibeaudiere, Yan Dhanda, Ollie Cooper, Morgan Whittaker.
Referee: Matthew Donohue