AITOR KARANKA admitted a half-time reading of the riot act was the key to Middlesbrough’s FA Cup third-round victory over Sheffield Wednesday.

The Teessiders booked their place in tomorrow’s fourth-round draw as second-half goals from Grant Leadbitter, Alvaro Negredo and Marten de Roon enabled them to overcome their Championship opponents.

They achieved their victory despite playing for more than half-an-hour with ten men following the 59th-minute dismissal of Daniel Ayala, and their second-half onslaught was completely out of keeping with a soporific first-half display.

As had been the case against Leicester last Monday, Boro failed to record a single shot on target in the whole of the first half, and Karanka was furious at his players’ lack of intensity in the opening 45 minutes.

He vented his frustration in the dressing room at the interval, and was delighted with his side’s response as they scored three goals in a game for only the second time this season.

“I told them at half-time that I thought we were playing a friendly game, and for me the FA Cup isn't a friendly, it's a really important game,” said Karanka, who is close to agreeing the departure of David Nugent in a £3m move to Derby County.

“In the way we've been preparing for the game this week, that wasn’t (how we) wanted to play this game. It's sometimes difficult against a team in a lower division to get the right mentality, but in the second half we went to the pitch with the right attitude.

“Even when we lost Dani, everyone was consistent, committed, fighting for every ball and that was the main thing.

“Yes (I was angry at half-time), as we weren't showing the right image. They came here knowing they were in the Championship and wanted to show everyone they can compete against us.

“In football, in every single game, if you don't go to the pitch 100 per cent then you'll have problems. Liverpool drew today (against Plymouth), so every single game is a good example that you have to give 150 per cent.”

Karanka was especially unhappy with his players’ failure to test Sheffield Wednesday’s rookie goalkeeper Joe Wildsmith in the first half.

The 21-year-old did not have to make a save before the interval, but he failed to get anywhere close to Leadbitter’s low 58th-minute free-kick and was left with egg on his face when his attempt at a hurried clearance cannoned off Negredo to hand Boro their second goal.

“I told the players at half-time they were playing against a third goalkeeper and we didn't know if he was good or bad,” said Karanka.

“We hadn't tested him, but Grant was intelligent with his goal, and after that it was much better. Two minutes later, Dani was sent off so I needed to change a few things, but playing with ten men, we showed good commitment.”

Ayala was sent off for a shoulder barge on Fernando Forestieri, with referee David Coote brandishing a straight red card even though there were other Boro defenders close to the Spanish centre-half.

It was a cynical act rather than a violent one, but Karanka is still to decide whether to appeal the red card, which would otherwise result in an automatic three-match ban.

“I don't know, at the beginning it was a surprise for everyone,” said the Boro boss. “But I was told by somebody that it was a red card, I haven't watched it back. I need to watch it (before deciding on an appeal).”

Rudy Gestede was an unused substitute five days after completing a £6m move from Aston Villa, and Karanka remains hopeful of making further additions before the transfer window closes.

He is also keen to move on a number of Boro’s fringe players, including Ayala, with Nugent likely to be the next player through the exit door as he prepares to join loanee Julien de Sart at Derby.

The Rams have signalled their willingness to pay £3m for the 31-year-old, who has scored nine goals in 45 games since joining Boro in the summer of 2015.