They have transformed themselves from a mid-table outfit into genuine play-off candidates.
Portuguese head coach Carlos Carvalhal has assembled a strong team, turning the Owls into a stylish passing side, who are a force to be reckoned with at this level, particularly in their own backyard.
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But they were unable to sign off 2015 on a positive note, losing for the second time this season to a classy, well organised Boro outfit.
It was a stark reminder that there is still much work to be done in the New Year if the Owls are to secure a place in the top six.
Carvalhal made wholesale changes, making six alterations to the side who cruised to a comfortable Boxing Day win over Birmingham City.
His gamble ultimately backfired as Cristhian Stuani’s strike after 44 seconds condemned them to a fifth defeat away from Hillsborough.
To cope with the “unfair” festive programme, Carvalhal rotated his squad, handing recalls to Liam Palmer, Rhoys Wiggins, Modou Sougou, Jose Semedo, Jeremy Helan and Lucas Joao. Out dropped Jack Hunt, Daniel Pudil, Ross Wallace, Fernando Forestieri, Atdhe Nuhiu and Gary Hooper.
Given Forestieri’s stellar goal-scoring exploits, it was a big call by Carvalhal to put the ex-Italy Under-21 international on the bench. Without Forestieri, they lacked the quality and imagination to cause Boro’s solid rearguard problems.
Middlesbrough, whose trip to Blackburn Rovers on Saturday was washed out, named an unchanged starting XI. In stark contrast to Wednesday, they had nine days to prepare for their final fixture of 2015.
It was understandable why Boro boss Aitor Karanka kept faith with the same side who superbly ended Brighton and Hove Albion’s 21-match unbeaten run last time out.
In front of the TV cameras against a refreshed opposition, Carvalhal fielded a team designed to contain Boro and hit them on the counter attack.
However, his new-look side made the worst possible start, conceding inside the opening minute.
Stewart Downing, in his second spell at his hometown club, was given far too much space on the left flank to whip in a teasing low cross which was turned in by Stuani for his 10th goal of the season. Wednesday’s marking was non existent.
Stuani’s early strike gave Boro, who boast the meanest defence in the Football League, a huge lift. The crowd were right behind Aitor Karanka’s men and full-back Emilio Nsue came within a whisker of doubling their advantage. His fierce strike was deflected narrowly over by last ditch challenge from Sam Hutchinson.
The Owls, lining up in a 4-1-4-1 formation with Semedo stationed in front of the back four and Joao deployed as the lone striker, struggled to cope with Boro’s high intensity pressing game. Boro kept on harrying and closing them down, forcing the visitors into unforced errors.
Semedo was lucky to escape a booking in the 13th minute after unceremoniously bringing down Boro playmaker Adam Clayton as Wednesday tried to put Boro under pressure.
But the contest remained extremely one-sided and Stuani came close to grabbing his second, planting a firm header straight at Wildsmith, who was deputising for the injured Keiren Westwood, following a peach of a delivery by George Friend.
Midway through the half, Albert Adomah floated in an inviting centre which Nsue dragged off target as Boro continued to dominate.
Wednesday rarely looked capable of troubling Boro. There was one bright, surging run from deep by Sougou. The Frenchman was barged over by Clayton, who became the first player to be yellow carded by referee David Coote.
Had Boro been more ruthless, they could have been out of sight at half-time, with the visitors failing to register a single shot at goal.
Carvalhal freshened things up at the interval, throwing on Forestieri and Pudil for Semedo and Hutchinson respectively. Czech Republic international Pudil moved to centre-back.
It didn’t take Forestieri long to make his presence felt, seeing his drive deflected over by Ben Gibson.
Wednesday looked far more threatening as an attacking unit following Forestieri’s introduction and Barry Bannan’s long range piledriver forced Dimi Konstantopoulos into a routine save.
More than 1,900 Wednesdayites made the trip to Teeside and Forestieri almost gave them something to shout about after Boro made a hash of dealing with a corner.
Carvalhal’s troops were much improved after the break, restricting Boro to few clear cut opportunities. Daniel Ayala, who shackled Joao superbly, nodded over at the back post Leadbitter’s inswinging set-piece.
It took an outstanding clearance off the line by Ayala to prevent Pudil from levelling things up in the 80th minute as the Owls kept passing and probing.
In the closing stages, substitute Atdhe Nuhiu’s looping header drifted over the top following a lovely centre by Barry Bannan but Boro’s defence held firm.
Victory moved them to the top of the pile and means they have not conceded a home goal since September 15. Only Leeds United and Bristol City triumphed at the Riverside Stadium this year.
Wednesday can take big encouragement from their second half showing, having been outplayed and outclassed in the opening 45 minutes.
It is no disgrace for Carvalhal’s charges to slip up away to a side who suffered just two defeats on home soil in 2015.
Nonetheless, if Wednesday are going to compete for promotion, they must improve their away form and start beating their rivals. Two wins from 12 attempts on their travels is simply not good enough.
On top of that, Owls have yet to beat any of the clubs directly above them in the table. That will have to change for Wednesday to push on in the second half of the campaign.
Middlesbrough: Konstantopoulos; Nsue (Amorebieta 89), Ayala, Gibson, Friend; Clayton, Leadbitter; Adomah (Fabbrini 62), Downing, Stuani; Kike (Kalas 73). Substitutes: Mejias, de Pena, Forshaw, Zuculini.
Wednesday: Wildsmith; Palmer, Loovens, Hutchinson (Pudil HT), Wiggins; Sougou, Lee, Semedo (Forestieri HT), Helan (Nuhiu 68); Bannan; Joao. Substitutes: Price, Sasso, Hunt, Wallace.
Referee: David Coote (Nottinghamshire)