The Red Devils have been unable to challenge their bitter rivals Manchester City for the Premier League title.
The Eastlands outfit have a 13-point lead over Jose Mourinho and his Manchester United team in the title race.
However, the 20-time English champions managed to spring a surprise in the Manchester derby last weekend.
Goals from Paul Pogba and Chris Smalling overturned a 2-0 deficit to allow the Red Devils to win 3-2 at Manchester City.
Manchester United have a four-point buffer over Liverpool FC and Tottenham in the race to secure a top-four spot.
The Red Devils can still win some silverware this season if Manchester United beat Tottenham Hotspur in the FA Cup semi-final to reach the Wembley showpiece.
Former Manchester United defender Neville believes the Red Devils need to win the FA Cup and finish in second place in the Premier League table.
“Man United have got to finish the season well. They have got to finish second. It would be good progression,” Neville told Sky Sports.
“It is not acceptable in the sense they should be challenging for the title. They’ve got to finish the season. They have that big FA Cup game in a few weeks. If Man United could finish the season second and win the FA Cup, you would still say that is momentum for Mourinho and Man United.”
Manchester United were 2-0 winners against Brighton and Hove Albion in the FA Cp third,
Manchester United signed Alexis Sanchez in a swap deal from Arsenal in the January transfer window.
The Red Devils finished in sixth place in the Premier League table last term but won the EFL Cup and Europa League.
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