AITOR Karanka admitted his frustration as his much-changed Middlesbrough side needed extra-time to defeat Burton Albion in the second round of the Capital One Cup.

Karanka made seven changes to the team that were beaten 0-1 by Bristol City at home on Saturday but saw his side come in at half-time trailing after George Friend turned the ball into his own net.

However, the rotated line-up prevailed at the Pirelli Stadium to set up a home tie with Championship rivals Wolves in the third round of the competition thanks to Cristhian Stuani – the Uruguayan levelling on 70 minutes before netting a winner in extra time.

And despite getting one over former Boro favourite Jimmy Floyd Hasselbaink, boss Karanka insisted it should have been far more plain sailing.

“I think we didn’t extra-time to win this game, because we had I don’t know how many chances to win before finishing," Karanka reflected.

“But I am really pleased, and really proud of my team, because all of them were brilliant; the players who played, the players who were on the bench, so really,LEFT OUT really pleased.”

“I told the players before the game that sometimes, these games are about mistakes, because we had the game the way that we want to.

“We had the game under control, but one set piece and one second ball, and we conceded an own goal.”

Boro enjoyed plenty of possession in the early stages, and missed a good chance to go one up after 17 minutes, when Stuani headed straight at Remi Matthews.

And they were soon made to regret that missed opportunity, when the unfortunate Friend saw a loose ball ricochet off his leg and past Tomás Mejías after a free kick in the 24th minute.

Chances came and went before the interval, when Karanka introduced Watford loanee Diego Fabbrini in place of Jack Stephens, and his side eventually drew level when Stuani converted a low Tomáš Kalas cross from close range.

Boro were unable to find a winner in normal time, but continued to dominate as the game went beyond 90 minutes.

And with Hasselbaink’s men running out of legs, Stuani struck again, this time drilling a Stewart Downing centre from the right into the bottom corner to send Middlesbrough through to the next round.

One of the players drafted in at Burton was Jonathan Woodgate, wearing the captain’s armband for his first appearance since the second leg of last season’s play-off semi-final against Brentford.

And Karanka was keen to emphasise the importance of the veteran centreback to the squad for the season ahead.

“Because of his experience, and he because he leaves everything on the pitch, he will always be a good example to the squad,” he added.

But Karanka refused to be drawn on the future of Ghanaian winger Albert Adomah who was omitted from the 18-man squad after rumours of a falling out with the manager.

“It was my decision (to omit him from the squad),” Karanka said. “He’s not injured. I have to select 18 players, and today I thought that the 18 players I selected were the best ones to win the game.

“I prefer to think and to speak about the players who have played today, and to say again how pleased and how proud I am of them.”