We self-destructed - Monk
Middlesbrough boss Garry Monk had mixed emotions after the 3-0 home defeat to Derby County.
Czech Republic striker Matej Vydra claimed a hat-trick for the visitors, while their opponents had defender Daniel Ayala sent-off after an hour.
The result found the two clubs therefore exchanging places in the Championship table, with Boro now slipping back out of the play-offs.
"Talk about shooting yourself in the foot," Monk reacted to BBC Sport. "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," he added. "But the difference was that the one time they were in our half, they were ruthless and clinical with it."