Speaking after Sunday's 2-1 defeat to Tottenham at White Hart Lane - the last game played at the historic ground - Mourinho admitted to reporters that finishing in the top four was no longer priority.
Manchester United are likely to field a weakened side as they travel to Southampton for their penultimate Premier League game of the season on Wednesday.
We, Manchester United, for us it is more important to win titles than to finish top four.
"When people say we gambled by going to Europa League, we didn't gamble".
"I have to build some teams with the minimum of conditions to fight for a result".
United have however done better out of the Europa League this season because other English clubs missed out on the later stages and so got a smaller share of the pooled payments.
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Indeed, United's struggles in the Premier League have continued this season under Jose Mourinho, and for the fourth campaign in a row the Red Devils will end the season behind Man City in the table. I don't know when we play the game. I can't stop thinking about what could have been... but that's life that's football, you win some you lose some.
Mourinho has been a constant critic of the fixture schedule this season, with runs in the FA Cup and Europa League adding to 38 Premier League games. [Daley] Blind will not play against Southampton, [Marouane] Fellaini will because he's not played the last three [league] matches [due to suspension].
"What I want from the players is a good attitude, positive attitude, positive approach, team spirit, an understanding that some guys have to sacrifice themselves for the sake of others", he said. "But we're all aware that our away form has been generally very good and our record is right up there with the top teams".
But while United expect to generate as much as £20m from the competition, that is less than half of the £50m the club anticipate they would earn from the Champions League.
"I want to congratulate all and say thank you to the fans, players, my staff because all together we work so hard to achieve all that we achieve this season", said Tottenham head coach Mauricio Pochettino.
Victor Wanyama and Harry Kane had given Spurs a 2-0 lead before Wayne Rooney got a goal back for United.
Boss Mauricio Pochettino said after they move to their new £800m stadium - following a temporary move to Wembley - the north Londoners can join the elite in Europe. Disappointment on our final visit to White Hart Lane.