Werder Bremen coach Thomas Schaaf admitted Diego's absence from the UEFA Cup final cost his side dearly.
The Bundesliga side lost 2-1 to Shakhtar Donetsk after extra time, but were never really in the game.
Much of the reason for that, according to Schaaf, was down to not having Diego.
The Brazil playmaker was suspended from the game after picking up a yellow card in the semi-final and Mesut Ozil, the man primed to take his place when he leaves at the end of the season, was unable to fill his boots adequately.
"We had such big plans but could not put them into practice," said Schaaf. "We noticed that we do not have a player who can replace Diego."
Director of sport Klaus Allofs refused to pin the reason for the defeat on Diego's absence, but admitted that the rest of the team had not played as well as they can.
He said: "We played below our standards against a strong opponent and we had too many players who were unable to call upon their true potential."
After dealing with the disappointment of last night's defeat in Istanbul, Bremen now turn their attention to the DFB-Pokal final against Bayer Leverkusen on May 30.
That now presents their only chance of obtaining any silverware this season after a disappointing campaign in the Bundesliga, where they will finish 10th no matter how they fare against league leaders Wolfsburg on Saturday.
And the speculation surrounding coach Thomas Schaaf's future is bound to increase, even if the coach, who is being linked with a move to Wolfsburg next season, would not comment on the rumours.