Manchester United defender Marcos Rojo has told ESPN Deportes that it has been "awful" to be knocked out of the Champions League.
Finishing in the Premier League's top four would earn a return to the Champions League, but United are currently a point adrift of fourth-placed Manchester City.
Asked about missing out on the Champions League, Rojo said: "It has been awful. It has made us very sad."
United's 1-0 win over Manchester City earlier this month boosted United's top-four chances, with Marcus Rashford scoring the only goal at the Etihad Stadium.
Rojo said: "I am happy with the derby result because we were out of the Europa League, so we were fighting to enter the Champions League. It was an important match to get fully back into the fight.
"Rashford is a great young player with an important future ahead of him, and I hope he keeps playing like that because it helps us a lot in each match.
"He is a player with a lot of potential. Despite his age, he is very confident and he shows it in each match."
United's win over City ended a run of four matches without a win, but Rojo backed coach Louis van Gaal, saying: "Louis is a great person and an excellent coach."
Rojo told TyC Sports that he wanted to return to Estudiantes when his contract expires in 2019, but that his focus for now remains on United and -- more imminently -- Argentina.
The 2014 World Cup finalists face Bolivia in a qualifying match for the 2018 tournament, having secured a 2-1 win over Chile on Friday, and Rojo said: "We are putting things on the right path. Now we have to get the next three points.
"We have to be focused. Our first rivals are ourselves. Leo [Messi] helps the team a lot -- the sky is the limit for this team."