Jose Mourinho will face his old club Chelsea in the quarterfinals of the FA Cup on Monday.Manchester United legend Gary Neville has suggested the Red Devils could sacrifice their FA Cup quarter-final with Chelsea in a bid to boost their Champions League qualification hopes.United are at Stamford Bridge on Monday for their FA Cup quarterfinal clash, and with qualification for next season’s Champions League directly from the Premier League looking daunting by the day, Neville believes they could prioritise the Europa League at the expense of the FA Cup.Read also: Chelsea v Man Utd preview | Conte, Mourinho renew rivalry"It comes down to what Mourinho prioritises,” Neville told Omnisport. "The FA Cup could be a competition that United sacrifice because they have to try and get into the Champions League."Obviously the only two routes are the Europa League and Premier League games. "It will be a big challenge mentally on Monday. It might be the one, at this moment in time, that they can sacrifice in terms of trying not to complicate the fixture congestion any more."The Red Devils are on course to win the Europa League, which will guarantee them a place in the Champions League next season, but were held to a 1-1 in the first leg by Rostov last week, and will face the Russians at Old Trafford in the return leg this week."I thought United would have a chance at the start of the season," Neville said. "But when Diego Costa and Eden Hazard turned up and they corrected their defensive problems by going three at the back, it became pretty apparent quickly that the old Chelsea were back."There's a lot of Premier League winners in that Chelsea team. The issue has been you don't know which Chelsea will turn up from one season from the next. Once the real Costa and Hazard turned up and you had David Luiz in defence and [N'Golo] Kante in midfield, you have a championship-winning team, or the makings of one."There is still a bit to go, they [Chelsea] still have some work to do. It won't be as comfortable as we think, there might be some dropped points in the next few weeks."The challenge at United was probably bigger than what everyone thought. When I look at it now, I don't think anyone could've won the league with United this season."