Carlos Carvalhal celebrated his 50th win as Owls boss with a morale-boosting victory over Chesterfield in the Carabao Cup.
It threatened to be an uncomfortable evening for the Championship club when the Spireites took a shock 38th minute lead through Kristian Dennis.
But Wednesday cruised into the second round following goals either side of half-time by Gary Hooper, Steven Fletcher, Barry Bannan, who was outstanding, and Sam Hutchinson.
The tournament is not high on the Owls’ priority list but they needed a strong performance following their dismal showing against Preston North End.
Progressing in the cup will lift everyone’s spirits following a difficult summer as Carvalhal brought up his half century in his 108th match in charge.
Carvalhal rested key players, including Keiren Westwood, Glenn Loovens, George Boyd, Jordan Rhodes, but he fielded a strong side. Joe Wildsmith, Almen Abdi, Ross Wallace, David Jones, Steven Fletcher and Gary Hooper were handed opportunities to shine.
In the first of three consecutive home matches, Wednesday made a strong start with Jack Hunt swinging in a dangerous cross from the right following a good driving run by Bannan.
Hooper and Fletcher, key figures in the Owls clinching a play-off spot last season, caused Chesterfield plenty of problems. Hooper volleyed narrowly over after a misplaced pass by Sam Hird before Joe Anyon produced a superb double save to keep Fletcher at bay after he had combined well with his strike partner.
Ross Wallace looked a major threat and he skipped past Sam Hird on the right only to see his delivery palmed away by Anyon.
As the rain continued to lash down on a grim, miserable evening in South Yorkshire, the Spireites created their first meaningful opportunity in the 20th minute, Chigozie Ugwu shooting over after seizing on a loose pass by Jones.
But Wednesday dominated possession and territory and Adam Reach, utilised at left-back, unleashed a rasping left foot shot from distance which Anyon did well to hang on to on the greasy, wet surface.
Chesterfield struggled to retain the ball and get out of their own half and the hosts launched wave upon wave of attacks and Wallace, Fletcher and Bannan all had sights at goal.
Against the run of play, the Spireites opened the scoring from the penalty spot. Kristian Dennis fired home from 12 yards after Daniel Pudil, filling in at centre-back, was penalised for handball.
Chesterfield’s opener could have rattled the Owls but they refused to buckle and hit back immediately.
After Anyon thwarted Fletcher, Hooper restored parity in the 43rd minute, firing home from an acute angle after latching on to Almen Abdi’s deflected centre. It was a superb finish by the former Celtic and Norwich City marksman.
And Wednesday, playing for the first time in their home strip, completed the stunning turnaround on the stroke of half-time, Fletcher rising highest to head in Hunt’s fine cross.
Carvalhal’s men looked hungry for more goals after the re-start and Bannan, who ran the show in midfield, saw his clever 20-yard lob hit the top of the net.
Jones, Abdi and Fletcher flashed efforts over as Wednesday piled the pressure on.
Hunt, who impressed offensively for the Owls, was taken off before the hour mark after picking up a knock.
Chesterfield, still smarting after their opening-day loss to Grimsby Town, could have made Wednesday pay for their profligacy in front of goal.
A lovely free-flowing move involving Bradley Barry, Ugwu and Louis Reed culminated in Dennis testing the reflexes of Wildsmith.
Former Owls striker Chris O’Grady wasted a glorious chance to make it two apiece. He fired into the side-netting after racing on to Ugwu’s excellent through ball.
It proved a good spell for the Spireites and Wildsmith had to be alert to parry away another Dennis strike at his near post.
But any faint hopes Chesterfield had of mounting a comeback were extinguished in the 75th minute when Bannan capped his terrific all-round performance with a wonderful solo goal. He glided forward and bent an exquisite effort past the helpless Anyon.
It was Bannan’s first goal in 11 months and it had been worth the wait.
Wednesday went for the jugular and Anyon was equal to substitute Sam Winnall’s powerful drive.
It proved a temporary reprieve as Hutchinson added a fourth following a strong burst into the box.
A brave piece of goalkeeping from Wildsmith kept O’Grady at bay in the closing stages. The pair collided and Wildsmith was taken off after receiving treatment. With the Owls having used all their subs, Hutchinson stepped up to don the gloves. He was not tested.