Jose Mourinho targets Champions League return - and Europa League trophy
Boro's record of just nine shots per game in the Premier League this season has them on course to record the lowest strike rate in over a decade, but with talents such as Alvaro Negredo and the lightning quick Adama Traore United will need to be on their toes if Agnew releases the shackles on his players for his first game in charge.
In an entertaining game, there was a fair share of blunders too with Chris Smalling guilty of one in the build-up to the Boro goal before the best was saved till last as Victor Valdes gifted Valencia the third.
Rashford, filling Ibrahimovic's centre-forward role, didn't score and missed a couple of very presentable chances - his finishing is not yet clinical enough overall, while his decision-making is still sometimes askew - but he still offered plenty to remind us that his is a talent to remain excited about.
"But it was tough in the end".
"I think the second goal is what set us back a little bit but in terms of the players, I couldn't be more proud of the players, the fighting spirit they showed, the crowd was top-class. It helped that we had a lot of defenders on the pitch to deal with that and we are pleased with the way we withstood their attacks".
A hard test but United pass, if only just: It's always challenging to come up against a side with a new manager, particularly when you have played 15 more games than your opponent, but Manchester United handled the task well and fully deserved the three points, even if it wasn't entirely convincing at times.
But the former assistant manager was unable to inspire his side to a fifth Premier League win this season despite dominating possession for large periods of the game.
Valdes had kept his side in the contest with a stunning double save to keep out a point-blank Marcus Rashford effort from Juan Mata's cross, before recovering to block the follow-up from Valencia.
United resume at home to West Bromwich Albion on April 1, which is the first of eight projected fixtures that month, including two Europa League ties against Anderlecht.
"Obviously, it has been a good week", Fellaini said.
"Because of the risk and for now we have Anderlecht [in the quarter-finals], but if we progress we have more and more risks and we may not win the Europa League, so we have to put everything also into the Premier League and try to finish fourth", he continued.
Manchester United returned to winning ways in the Premier League with a 3-1 win over struggling Middlesbrough. "We have a lot of games coming up - tough games against teams like Spurs, Arsenal and Man City, so we will keep fighting to win all of them".
He added: "We have a big squad with quality".