Aitor Karanka, however, was not displeased with his Middlesbrough team's performance which resulted in his side's first loss in four matches.
Karanka not disheartened following defeat
“We once again showed that we can compete against the best teams in the league," commented Karanka after his side lost 1-0, having seen his side concede following a lapse in concentration from a corner.
“To concede a goal from a set-piece is a mistake but I don’t want to blame any player because I always say we win as a team and we lose as a team."
The Spanish head coach also added he was "really pleased with the attitude of the players," and that Middlesbrough "are going in the right direction."
Despite Chelsea coming away with all three points, Boro had some good chances to score against Antonio Conte's men. Alvaro Negredo hit a volley which was saved by Thibaut Courtois after Gaston Ramirez had fired over from 18-yards out.
Praise for the away side
"We knew it was going to be a really, really tough game," acknowledged Karanka, who revealed he turned down the opportunity to be assistant manager at Stamford Bridge when Jose Mourinho returned to London.
The Boro boss added that Chelsea "defend together, they are really dangerous in transition, they have players with the quality to play in different ways."
Karanka also commented that his side needed to have been at "100% and not make one single mistake" in order to win the match.
Worrying news for George Friend
After the match, Aitor Karanka assessed the injury that George Friend has suffered in training during the week.
The left back, who has captained Middlesbrough for 10 of their 12 Premier League games this season, will miss the rest of November with the injury.
Aitor Karanka told the press that Friend is expected to be out for "two to three weeks."
The injury was initially thought to be a knock but has since been confirmed to be worse than first thought.