⁠Middlesbrough FC could have paid the price for drastic Aitor Karanka action | OneFootball

Aitor Karanka's Middlesbrough walkout in the midst of Boro's Premier League promotion push in 2016 remains a hugely shocking moment.

The 2015/16 Championship season will live long in the memory for Middlesbrough supporters, but an Aitor Karanka walkout threatened to derail Boro's Premier League promotion push entirely.

It had been a testing time at the Riverside Stadium prior to Karanka's appointment in November 2013.

Middlesbrough's relegation from the Premier League in 2009 was followed by a disastrous Gordon Strachan era on Teesside, before Tony Mowbray arrived to steady a rapidly sinking ship from submerging into League One in the 2010/11 season.

Having laid the foundations for success, "Mogga" would eventually pass the baton onto Karanka, who would become the first foreign manager in the club's history.

Guiding the club to a mid-table finish in the 2013/14 campaign, José Mourinho's former Real Madrid assistant would lead Middlesbrough to the Championship play-off final the following year, which they would lose to Norwich City.

However, optimism was rife on Teesside that Premier League football was just around the corner under the Spaniard. They were right too, but had one unforeseen and shocking event ended differently, that top flight return may never have came.

Middlesbrough look to be on course for Premier League promotion come the final weeks of the 2015/16 season

Putting a play-off final defeat and the knowledge of missing out on the Premier League behind them, Middlesbrough marched into the 2015/16 season with an air of defence about them.

Those that remained from that fateful day at Wembley Stadium had scores to settle and demons to banish, and they made sure to take their anger and frustration out on the rest of the Championship.

Boro lost just one of their opening nine league fixtures, winning six of them, and after going unbeaten in the league through a hectic and crucial month of December, Karanka's squad found themselves welcoming in 2016 at the top of the Championship table.

Boro had seen off a number of their promotion rivals that month, with wins over Ipswich Town, Burnley and Sheffield Wednesday, as well as a memorable afternoon at the Amex, as a travelling Teesside army saw their side dispatch Chris Hughton's Brighton 3-0.

With the two sides meeting again on the final day of the season, nobody could have predicted then how much would be at stake the next time these two heavyweight contenders would clash that year.

Middlesbrough would endure somewhat of a rocky start to the new year though, with Karanka's side winning just two of their opening seven league games in 2016.

Despite that, Boro still headed into March sitting joint-second in the table with Hull City on 64 points, whilst top of the league Burnley were just a point away on 65. It was all still there in front of them for the Teessiders.

Aitor Karanka unexpectedly walks out on Middlesbrough squad, plunging Boro's season into limbo

After a 2-1 defeat away at Blackburn Rovers was quickly followed up with a 2-1 home win against Wolves, Middlesbrough looked to have two straightforward six points on paper awaiting them.

Rotherham United were occupying the final relegation spot in 22nd place when Boro rocked up at the New York Stadium, and as such, Teessiders were understandably full of confidence that this would be a routine victory for Karanka's men.

However, a dark and gloomy Tuesday evening in South Yorkshire was to follow. David Nugent blazing a one-on-one effort over the crossbar before a Gaston Ramirez free-kick rattled the post; it was turning into one of those nights for Boro.

Still, if you can't win a game of football, you mustn't lose it. Well, Middlesbrough forgot that valuable lesson that night, as Neil Warnock's Millers struck in the dying stages of the game, as Lee Frecklington fired the ball into the roof of Dimi Konstantopoulous' net in the 88th minute.

Boro had just a matter of days to lick their wounds, as a trip to The Valley to take on a relegation-threatened Charlton side awaited them at the weekend, but little did anyone know that a shocking turn of events was about to threaten Middlesbrough's entire season.

Middlesbrough's game with the Addicks was on Sunday, but following a row during a squad meeting on the Friday, Karanka stormed out of the club's Rockliffe Park headquarters. It was during that meeting that the Spaniard had reportedly told his players he no longer wished to be their manager.

It was believed that Karanka's frustration had arisen from the club deciding to sign Blackburn striker Jordan Rhodes over his preferred target of Fulham's Ross McCormack, whilst there was also suggestions of a falling out between him and Boro winger Stewart Downing.

After holding crisis talks with club officials that same evening, Karanka turned up to Boro's training ground the following morning to take charge of a light training session before the squad departed for South London, but Middlesbrough chiefs instructed him to return home after regarding his presence as being too divisive.

Steve Agnew was Karanka's assistant manager at the time, and it was he who took charge of the team for their meeting with Charlton. Unfortunately, it was a performance that showed all the signs of a squad in shock, and the Addicks were in no mood for sympathy, as they ran out 2–0 winners on the day.

Karanka returns to Middlesbrough post and guides Boro to Premier League promotion

With their manager abandoning his post and nowhere to be seen, and having witnessed their side record back-to-back defeats to two of the bottom three sides, panic was beginning to set in amongst the Middlesbrough supporters.

Their next game would be a huge home clash with Hull City, with the Tigers just one place and one point below third-placed Boro, who knew that win at the Riverside would send them back into the top two.

However, much to the relief of everyone connected with the club, Karanka agreed to bury the hatchet and return to his role as Middlesbrough manager ahead of that fixture of monumental importance with just 10 games to go in the season.

That Friday night by the banks of the River Tees was a watershed moment in Middlesbrough's campaign, as a stoppage time David Nugent header handed Karanka's side a crucial three points, and signalled the start of a Teesside charge for the Premier League.

Middlesbrough went unbeaten in the Championship from that game forward, with memorable comebacks and late winners against Reading and Bolton respectively, before a final day showdown for automatic promotion against Brighton.

Boro needed just a point against the Seagulls to secure automatic promotion back to the Premier League, and thanks to a Cristhian Stuani goal and one almighty catch from Konstantopoulos in added time, that's exactly what they would get.

Karanka's side finished the 2015/16 Championship season in second place, retaking their place in the top flight for the 2016/17 season.

They would concede just 31 times in the league that year, which was the fewest of any side in English football's top four divisions that season. Boro also broke a club record for the most consecutive home clean sheets with nine.

Karanka had been instrumental to making Middlesbrough one of the toughest to beat teams in the Championship, and had he vacated his post permanently that March, then having to potentially change managers or stick with Agnew at the stage of the season could have had catastrophic consequences to the outcome of their campaign.

However, it remains one of the most shocking and surprising moments in Middlesbrough's recent history.