Fletcher single-handedly tormented Wigan's defence. His aerial prowess and physicality proved too much for centre-backs Chey Dunkley and Cedric Kipre. He bullied them.
Fletcher led the line intelligently, won his aerial battles and repeatedly demonstrated that he has got a lovely touch for a big man.
He put in a tireless shift and scored a lovely solo goal.
Following good build-up play from Adam Reach and Barry Bannan, Fletcher collected possession from deep and ran at the Latics dishevelled back four. The space opened up for him and Fletcher curled a spectacular 25 yard shot past Jamie Jones. It was an outstanding finish and a rare moment of class.
"He was fantastic," acknowledged Owls defender Michael Hector. "He won almost every header.
"With the goal, his finish, you could see the quality.
"He is a big player for us and that performance showed why."
Wigan must be sick of the sight of Fletcher, who has now scored seven goals in his last seven league appearances against the Lancashire club.
Caretaker Wednesday boss Steve Agnew said: 'I spoke to him yesterday (Friday) '“ Â it's almost his third game in a week '“ and I said, '˜How do you feel?' He said, '˜I feel great'. There were no knocks, no tightness and that's how he performed.
'He looked fresh, he looked lively, he won almost every header and he deserved his goal.
'If you ask their two centre-backs, that was probably one of the hardest games they will have had all season.
"When the ball was going up to Fletch, they were dropping off him and I think that's a mark of respect because when they did get tight, he invariably won either the header or played round them."
After an uninspiring first half devoid of clear-cut chances, the Owls took complete control of the second period. They played at a higher tempo and wasted a host of opportunities to score more goals after Fletcher's sublime strike.
It was easy to see why Wigan have one of the worst away records in the division. The visitors hardly tested Keiren Westwood in Wednesday's goal.
'We stressed to the players before the game to play on the front foot and make things happen in the final third," said Agnew.
'We went a little bit long up to Fletch in the first half. I said to the players at half-time that the game was there to be won if we lifted our game a little bit more with our passing and movement and I thought we did that. We played better in the second and made some good chances.
'We took the game to them. Fletcher got a well-deserved goal '“ he was a handful all afternoon.Â The combination play between Adam Reach and Barry Bannan, to get the ball to Fletch, started a terrific move and finished off nicely by Fletch.
"We had a higher press which was evident by the fact that they never got in and around our goalmouth to have a shot at goal.
'If I have a criticism, I would have liked to have seenÂ a second goal but we will take the three points.'
The Owls carried a greater attacking threat in the final half an hour when they switched to two up front. Lucas Joao, fit-again after shrugging off a hip problem, injected some much-needed pace and helped stretch Wigan's tiring defence.
Hector said: 'I think we dominated from start to finish. It was a comfortable goal game for us.
'We would have liked to have scored more goals, but a clean sheet is a big bonus after last Saturday (at Hull). Our performance, on and off the ball, was really good.'
THE BEST TEAM WON
Wigan boss Paul Cook was magnanimous in defeat after watching his side slip to an 11th away loss.
'Sheffield Wednesday got on top second half," he said. "They created chances, they created good situations and for me they're deserved winners. We go away very disappointed."
The former Chesterfield chief refused to criticise his team for failing to stop Wednesday matchwinner Fletcher, saying: 'Steven Fletcher is just a good player. If you look back at his career, he's done quite well so I'm not going to be critical of my players."
Fletcher was the difference between the teams and Chelsea loanee Hector has witnessed first hand what Fletcher is capable of on the training pitch.
"In training, we had a '˜young v old' and he caused me a lot of problems," he said. "You want to train with players like him, good quality players, it's the only way you are going to get better.
"He is aggressive, has skills, strong, and you can see see he has played in the Premier League. He has that quality."
Fletcher received a big round of applause when he was substituted with eight minutes remaining and replaced by Nuhiu. He fully deserved that send-off, having runÂ Wigan ragged.
Chelsea, you have been warned!