BREAKAWAY second-half goals from Diego Fabbrini and substitute Christian Stuani nipped a second-half fightback from the Owls firmly in the bud as Boro ended their Hillsborough hoodoo.
Boro led at the interval thanks to a goal just before the break from Adam Reach but the Owls were much-improved on the restart and levelled on 64 minutes through Marco Matias’ strike, which deflected in off Ben Gibson and looped over Dimi Konstantopoulos.
The goal provided the catalyst for the Owls, but three minutes later, they were hit with a sucker-punch with the ball breaking on the left for Fabbrini, who was afforded oceans of space as the hosts were caught with numbers upfield and he advanced on goal before coolly steering the ball past Lewis Price.
Boro sealed it four minutes from time when sub Dave Nugent set up fellow replacement Stuani on the left and his clinical low shot beat Price.
The Owls were handed a double boost ahead of the game, with the club completing the signing of Watford’s Fernando Forestieri on a four-year deal for an undisclosed fee, with the Italian present to watch proceedings.
His signing followed the capture of his Hornets team-mate Daniel Pudil, who has joined the Owls on a season-long loan.
Head coach Carlos Carvalhal made four changes from midweek with Atdhe Nuhiu, a nemesis for Boro in recent seasons after netting four goals in his last three appearances against them, dropping down and having to settle for a spot on the bench.
Fit-again Lucas Joao, Rhoys Wiggins, Matias and Sam Hutchinson also returned to the Owls starting XI, with their being no place on the bench for Sergiu Bus or Caolan Lavery.
There was no place in the Boro line-up for unsettled winger Albert Adomah, who dropped a bombshell on Thursday afternoon after submitting a transfer request.
As expected, Aitor Karanka made a number of changes following the extra-time win at Burton in the Capital One Cup in midweek, with Dimi Konstantopoulos, Emilio Nsue, Daniel Ayala, Diego Fabbrini, Adam Clayton and Stewart Downing returning to the starting line-up.
It was a half in which Boro dominated possession, while in contrast, Wendesday looks disjointed and devoid of ideas in a disappointing showing.
The Teessiders forged a deserved lead on 42 minutes when Reach lashed home from close range after the Owls failed to clear an inswinging corner on the left from Grant Leadbitter, with the winger’s effort going into the net via the aid of a slight deflection.
Boro almost doubled their lead shortly after with Reach almost in after a mix-up between home captain Tom Lees and keeper Lewis Price, with Ross Wallace firing a free-kick wide in a rare attack at the other end before the Owls were afford the welcome sanctuary of the dressing room at the interval to regroup.
The hosts failed to trouble Konstantopoulos in a lame first period, with their best and only moments of enterprise coming from Joao, who looked the man most likely.
The pacey striker dragged an early effort wide and saw a low shot saved on the half-hour.
It was Boro who bossed possession and territory, with their first chance coming to Downing, who lashed a half-volley wide into the Kop after his earlier free-kick was blocked shortly before.
Boro continued to knock at the door and it took a smart tip-over from Price on 16 minutes to keep out Ayala’s header following Clayton’s pinpoint cross.
The Owls made an enforced change on 22 minutes when Hutchinson, injured in a challenge, was replaced by Semedo in a like-for-like change.
Downing then failed to get power on his shot after being teed up by Reach before Ben Gibson received a yellow card after clattering Joao.
Price soon beat away a Reach piledriver as Boro upped the ante further , but he could not stop the winger putting Boro ahead before the interval.
Carvalhal made a wise change at the interval, bringing on Nuhiu for Wallace and reverting to a two-man forward line to pep up the Owls.
The switch did the job of rousing Wednesday into life and they were much-improved on the restart and showed much more zest and purpose.
Alex Lopez went close with a snapshot which whistled just wide before he saw his free-kick draw a good save from Konstantpoulos, who palmed away his effort which was destined for the top corner.
With Nuhiu proving a nuisance and Matias getting into the game, the Owls suddenly were displaying menace, with Boro forced onto the retreat for the first time.
Two minutes before the hour mark, Dave Nugent replaced Kike in a bid to wrestle the initiative back for Boro, who had a half-chance on the break with good work on the right by Nsue almost providing a clear sign on goal for Reach, but his outstretched leg couldn’t divert the cross goalwards.
Wednesday then draw level on 64 minutes when Hunt’s cross was only half-cleared and the ball broke on the edge of the box for Matias, who nutmegged Clayton before seeing his shot loop into the net off Gibson.
The initiative was with the Owls for just three minutes, thanks to a lovely precision finish from Fabbrini, although questions have to be asked of the home defence, who went AWOL.
To their credit, Wednesday still put pressure on the Boro defence and Tom Lees was within a whisker of levelling on 79 minutes with his header flashing just wide following a Lee corner.
A Nuhiu shot then diverted into the path of Lee in the box and for a split-second, it looked like he would have a clear sight on goal, but his effort was blocked by Grant Leadbitter.
Stuani eased any nerves in the away end by hitting Boro’s third on the counter as the Teessiders, with six losses in their previous seven games at S6, finally afforded some cheer.
Wednesday head coach Carlos Carvalhal said: “We played against one of the strongest teams in the Championship and we played very soft.
“We gave the ball to the opponents in the first 45 minutes and then we changed things. We tried to be more aggressive.
“There was a strong reaction and we started to create opportunities. We scored the goal and continued to try to win.
“We gave a lot to make it 1-1 and after they scored again, it was difficult for us. It had a big impact on our players and it was very hard after that.
“The big lesson we must take from the game is that we must play from the beginning.
“Today we have brought in two more players (Daniel Pudil and Fernando Forestieri). We believe we’ll have more quality and more options.”
Middlesbrough head coach Aitor Karanka said: “I am proud of my team. All the players did well because it was a difficult game, especially after our defeat last Saturday at home. The reaction we had after they equalised was really good.
“We played really, really well in the first half and in the second half with (Atdhe) Nuhiu on the pitch we knew it was going to be much more difficult because he’s a player who can change everything. Last season we had a lot of problems to stop him and when he was on the pitch it was difficult.
“This season I have players on the bench who can change games. I had players on the bench like Adam Forshaw, Stuani and David Nugent. You feel that they can make a difference on the pitch.
“When players are on the bench sometimes they are not happy, but they understand and they are always fighting for each other.”
Sheffield Wednesday: Price; Hunt, Lees, Sasso, Wiggins; Lee, Hutchinson (Semedo 22), Lopez (Sougou 76); Wallace (Nuhiu 45), Joao, Matias. Substitutes unused: Wildsmith, Palmer, Turner, McGugan.
Middlesbrough: Dimi, Nsue, Ayala, Gibson, Friend, Leadbitter, Clayton, Downing (Stuani 68), Fabbrini, (Forshaw 84), Reach; Kike (Nugent 58). Substitutes unused: Mejias, Stephens, Kalas, Woodgate.