Bitterly frustrating: Boro boss Garry Monk's reaction to stunning Derby defeat

Matej Vydra’s hat-trick pushed Boro out of the play-off places, in a game which saw defender Daniel Ayala concede a penalty before being sent off.

Monk felt his side had performed reasonably well in the first half, with Britt Assombalonga and Fabio Da Silva both wasting decent headed chances to score.

However, the Boro boss conceded that his players had made a succession of dreadful second-half errors.

“Talk about shooting yourself in the foot,” said Monk. “It was so disappointing to go from playing that well in the first half, where we played some of our best football of the season.

“The one disappointment of the first half was that we weren’t ruthless enough. With the chances we created, we should have been winning that game at half-time.

“But the difference was that the one time they were in our half, they were ruthless and clinical with it.

“It was a difficult one at half-time because we had been playing at a good level, and if we had continued playing in that way, you couldn’t see anything else than us getting back into the game and being in a good position to win it.

“But the second half was horrible. We shot ourselves in the foot with individual mistakes and errors. That’s what cost us, and it was bitterly frustrating.”

The hosts would have opened the scoring in the 11th minute but for a terrific save from Scott Carson. Cyrus Christie’s long throw was headed on by Ayala into the path of Assombalonga, but he was denied from point-blank range.

Within a minute, Derby led when Vydra played a neat one-two with Tom Lawrence before rifling the ball into the roof of Boro’s net.

Monk’s men continued to create chances, the best of which fell to full-back Fabio when the Brazilian headed Christie’s cross over the bar.

However, Boro lost their momentum within seconds of the restart when Martin Braithwaite conceded possession before Ayala clumsily felled Vydra inside the area.

The Czech calmly doubled the lead from the spot, converting low to Darren Randolph’s left after the keeper dived the other way.

Ayala, already on a yellow card, clattered into the back of former Boro striker David Nugent and wasduly sent off.

Derby added a third in the 63rd minute when Randolph was put under pressure by Ben Gibson’s back-pass and shanked the ball into air. Vydra was there to pick up the pieces and smashed home.

Middlesbrough: Randolph, Christie, Ayala, Gibson, Da Silva, Forshaw, Clayton, Downing (Bamford 80), Braithwaite (Fry 67), Johnson (Traore 55), Assombalonga. Subs not used: Konstantopoulos, Friend, Leadbitter, Fletcher. Sent Off: Ayala (60). Booked: Ayala, Da Silva.

Derby: Carson, Baird, Keogh, Davies, Forsyth, Huddlestone, Ledley (Russell 84), Weimann, Vydra (Thorne 67), Lawrence, Nugent (Martin 67). Subs not used: Wisdom, Pearce, Olsson, Mitchell. Booked: Huddlestone, Ledley. Goals: Vydra 13, 47 pen, 63.

Att: 24,607. Ref: Simon Hooper (Wiltshire).