United lost 2-1 to Valencia on Wednesday in the Champions League as Phil Jones’ own goal compounded Carlos Soler’s first-half strike, before substitute Marcus Rashford scored a late consolation.
With Juventus surprisingly losing to Young Boys, United missed the chance to finish top of Group H and Mata admits slow starts to games are hurting them.
“It seems like we always push in the last minutes, when players come off from the bench or the players that are on the pitch.
“It seems like we react in the last 10, 15 minutes and start creating more chances and getting closer and closer to score. That is what we did today but it was not enough.
“We are disappointed because obviously it’s more painful knowing that Juventus lost and if we had have won we would have finished first in the group.
“It was special for me personally coming back to Valencia and feel the love of the club and the supporters, so I am grateful for that, but disappointed overall. We reacted a bit too late,” Mata told Sky Sports.
