Aitor Karanka admitted Ben Gibson’s sending off made Middlesbrough’s task of trying to earn at least a point at Watford more difficult, but didn’t believe his side played to their best in the 1-0 defeat at Vicarage Road.

Although Boro were trailing to Troy Deeney’s penalty early in the second half, the momentum was in their favour soon after when Samba Diakite received a straight red card for a two-footed challenge.

However, the visitors’ numerical advantage in terms of players was quickly cancelled out after Gibson picked up a second yellow card for trying to prevent Jonathan Bond from clearing.

“I didn’t see it but it’s a mistake,” the Boro head coach said of Gibson’s dismissal. “When you have one yellow card, you can’t do this. You need to be more intelligent and we lost the game for our mistakes.

“We were losing but we were one man more and I thought with the three subs I had we could change the score but five minutes later Gibson was sent off and the game was very, very difficult.

“The problem is the mistakes. It’s not the mentality or the capacity of my players because we played today at 100 per cent like we played a lot of games in the past. We could beat Watford playing with 11 players, playing with ten players but when we don’t play like we can it’s difficult to win.”

This was Boro’s fifth consecutive game without scoring and asked about the lack of goals, Karanka replied: “Sometimes it can be luck but sometimes it’s because you didn’t do everything to score goals and when you don’t do those those things it’s more difficult.

"Today and other games, like Doncaster, we didn’t do the good things. We played very well in the last game at home to Blackburn and we had a lot of chances and I thought we were unlucky but today I didn’t.”