MANCHESTER, England -- Ruben Amorim will hope that one day, the FA Cup will slip down his list of priorities.

Right now, though, with Manchester United languishing in the bottom half of the Premier League table, it's offering some welcome respite for the under-pressure manager.

Nothing is coming easy for Amorim at the moment and United, who handed a debut to January signing Patrick Dorgu, had to fight back from a goal down to beat Leicester City 2-1 at Old Trafford on Friday. It required a stoppage time header from Harry Maguire -- which appeared to be offside -- to book United's place in the FA Cup's fifth round.

But the most important thing for Amorim is that they've advanced, and hardware is still on the line.

It has been tempting for some supporters to believe that the club has written off the rest of this season, particularly after a quiet January transfer window with little effort made to add a new attacker. At least the FA Cup offers something to keep fans interested.

Until Amorim can turn this team around to the point where title challenges become the norm -- and that seems a long way off right now -- he needs to cling to every small success he can.

"It was a good result, not a good performance," Amorim said. "I think the performance, we have to do so much better with the ball, without the ball. Today is a feeling of the win, and the fans go home with that feeling of win.

"It's hard to point to something to give them [the fans] confidence, just the spirit in the second half, more energy, more second balls. The rest, there is a lot to improve. We already knew that we need to do better."

Amorim has repeatedly warned supporters that things could get very messy between now and the summer, when he'll have a chance to bring in his own players and time to work on the training ground. Home defeats to Bournemouth, Newcastle, Brighton and Crystal Palace have proved him correct.

United aren't good enough at the moment for the week-in, week-out battle of the Premier League. The good news for Amorim is that you don't need to be consistent in the FA Cup.

You just need to be good a little bit, and in fits and starts. Throw in a little bit of luck and you can get quite close to Wembley. Maybe even win the whole thing. And United were fortunate to get through the FA Cup last round when Arsenal failed to take advantage of Diogo Dalot's red card and lost on penalties at the Emirates.

Even with all their problems, Amorim's team were expected to beat Leicester, a side rooted in the bottom three in the Premier League -- but United still struggled.

The first half was so poor that they couldn't muster a single shot on target as Ruud van Nistelrooy's team went in at half-time deservedly 1-0 up. United's first-half expected goals tally of just 0.05 was tied for the lowest in Amorim's 20 games in charge.

The game only changed in the second half with the introduction of substitutes Alejandro Garnacho and Joshua Zirkzee. Even then it was a slog. Zirkzee scored to make it 1-1. But just as extra time beckoned, United were awarded a contentious free kick by referee Michael Salisbury after the ball flicked up off Garnacho and hit James Justin's elbow.

It was United's first bit of luck. Salisbury put the whistle to his lips, pulled it away again and then finally blew. Van Nistelrooy raged on the touchline and before the Dutchman had calmed down, Bruno Fernandes floated his cross into the box and Maguire headed in the winner.

Replays showed Maguire was at least a yard offside, but with no VAR until the next round, the goal stood. United's second -- and decisive -- piece of luck.

"VAR you have in a couple centimetres, a couple of inches; this was half a metre, clear in line," Van Nistelrooy fumed afterwards. "That was a hard one to take because the team deserves to draw in the end.

"Then extra time, stay in the game, you never know what happens. We deserved to go into extra time, go for the battle in extra time and maybe penalties. Decisions like these in our level are hard to swallow."

Even Amorim admitted the call was wrong, but such are the rules of the FA Cup.

"With VAR it was not a goal, and I think it's important to have because it's fair," Amorim said. "It's really hard to lose one game in the last minute with an offside play, but sometimes we deserve a little bit of luck."

At the moment, United need it.

The victory over Leicester was United's third in four games, but afterwards Amorim looked like a man whose worries have deepened rather than eased. It was the type of performance that will do that to a head coach. He has seen lots of them since taking over for Erik ten Hag in November.

The danger is that United could serve up the same in their next two games -- tricky away fixtures against Everton and Tottenham. They are two of only seven teams below them in the table, and if results don't go United's way, they could conceivably be 16th in two weeks. That would make things far messier than even Amorim anticipated.

At least he has another FA Cup tie to look forward to. It was a close call, but the competition continues to offer a glimmer of hope in an otherwise wretched campaign.