Head coach Aitor Karanka is positive Middlesbrough can achieve their Premier League ambitions, despite losing the Championship play-off final to Norwich.
Monday's 2-0 defeat at Wembley ended Karanka's first full season in charge, which saw Boro's best league finish since exiting the top flight in 2009.
The Teessiders finished fourth, an improvement on last term's 12th place.
"One day I am sure we will be in the Premier League, I prefer to remain positive," Karanka told BBC Tees.
"To think where we were 18 months ago [when Karanka took charge], we were five points above the relegation zone, now we're playing at Wembley.
"We were expecting to be in the Premier League because this squad has playing amazing all season but we made mistakes."
Boro's downfall came in a three-minute first-half burst from which they never recovered, as Cameron Jerome and Nathan Redmond fired Norwich into an unassailable position.
Defender Daniel Ayala was brushed off easily by Jerome for the opener and goalkeeper Dimi Konstantopoulos was beaten at his near post.
"You can't make mistakes in a one-off final, if you make them you pay," said Karanka.
"We lost but I don't want to say anything out about individual mistakes.
"The fact we are here at Wembley was because we played as a team, we win as a team and we lose as a team."
Teessiders chairman Steve Gibson congratulated the Norwich players in the Royal Box as they received the trophy and medals at the end of the final, despite his own disappointments.
His nephew Ben Gibson was a member of the Boro side which was unable to complete the task of winning promotion after 49 games, despite two league victories over the Canaries, at home in November and at Carrow Road in April.
"We didn't do ourselves justice," added Gibson.
"We've improved on last year and we've got to try to improve again.
"It means as much to us as to them and we're distraught. If you get beaten by a wonder goal or a team that's better, you hold you hands up - but we beat them twice. They handled the occasion better than us."