Middlesbrough chief Aitor Karanka defended his rotation policy following the defeat, with many bemused by the absences of Ben Gibson, Albert Adomah, Kike and Diego Fabbrini from the starting line-up.
He said: “I always have to choose the best XI for the game and today I decided to make some changes to that and it didn’t work.
“When I pick the team, I always have reasons for doing things. For example, Fabbrini didn’t play pre-season with us and has a lot.
“Gibbo played on Tuesday but he hasn’t had pre-season. Kike played three games in a row and (David) Nugent was fresh, which I thought would have been good for us.
“The same with Adomah; I felt he looked tired on Tuesday and for that reason, I thought he needed a rest.”
Karanka added: “It’s difficult for me to understand the performance. I don’t know what happened; we didn’t play how we usually do.
“We had very good players on the pitch and it’s difficult to understand. I have to analyse what happened.”
Steve Cotterill revelled in City’s first win since their return to the Championship after Joe Bryan grabbed the only goal.
City chief Cotterill, who felt the win was overdue following some impressive, if unrewarded, performances, said: “I am delighted. Hopefully, that will give us the confidence we need. If Middlesbrough don’t get automatic promotion, they will certainly be in the top six.”
Middlesbrough: Konstantopoulos, Nsue (Garcia 76), Ayala, Kalas, Friend, Clayton, Leadbitter, Stuani (Adomah 62), Downing, Wildschut (Fabbrini 46), Nugent. Unused substitutes: Gibson, Mejias, Stephens, Forshaw.
Bristol City: Hamer, Little (Fredericks 70), Ayling, Flint, Williams, Bryan, Pack, Smith, Reid (Wagstaff 78), Wilbraham, Kodjia (Burns 62). Unused substitutes: El-Abd, Robinson, Agard, O’Leary.
Referee: P Tierney (Lancashire).
Man of the match: Joe Bryan.