Alexis Sanchez, Paul Pogba key to Jose Mourinho hopes of Manchester United title challenge

At the beginning of last season, we looked at the 15 potentially most important players for Manchester United. With the new season underway, who are the risers and fallers?

This list is not extensive and has been ranked according to varying factors. Some players still with a part to play, like Mateo Kovacic, have been omitted. Performance, potential, the ability to make an impact and influence the course of a game, other options in that area of the field, the ability or inability to replace them and market value have all played a part in revising the 15.

1. Alexis Sanchez (new entry)

The Chilean is the type of player who could be the difference between a title challenge and another season spent watching Manchester City run away with it. If he can rediscover the form that saw him score 24 league goals for Arsenal in 2016-17, United will be a lot closer to Pep Guardiola's team come May.

2. Paul Pogba (+1)

The Frenchman is one of United's best players and, because of that, one of their most important. He was fantastic against Leicester on opening night and if he can re-create that week after week, United will be a much better team. Pogba's talent is not in doubt, just the consistency of his performances. He proved against Manchester City last season that he can also be the difference in the big games, scoring twice from 2-0 down to win 3-2 and ruin their supposed title party.

3. Romelu Lukaku (-2)

Lukaku is the only genuine centre forward in Jose Mourinho's squad and so the responsibility in front of goal will fall primarily on his shoulders. He scored 27 in all competitions last season -- a good return in his first year at Old Trafford -- but he will be expected to build on that this year. A tally of around 25 league goals this season is a fair target for someone of his ability and should put United much closer to Manchester City.

4. David De Gea (+1)

The Spaniard is always important to United -- he's won the player of the year award in four of the past five seasons. Some of the things he makes look routine are far from it and Mourinho will need his goalkeeper to be at his best again this season. United had the second best defensive record in the league last year and that had a lot to do with De Gea's form.

5. Eric Bailly (-1)

Mourinho tried desperately to bring in another centre-back in the summer but didn't manage to do it. Because of that there will be extra responsibility on Bailly, generally considered to be the best of United's five centre-halves. He has rarely had a bad game since arriving at Old Trafford but there is a question mark over his injury record. He only managed 13 league games last season and Mourinho needs the Ivorian to stay fit.

6. Nemanja Matic (-4)

The Serbian will be first-choice this season and if Mourinho isn't entirely convinced by his centre-back pairings, Matic's job shielding the back four will be important. He had a good first season at Old Trafford and despite turning 30, will be expected to be ever better this term.

7. Antonio Valencia (no change)

Much of the width in Mourinho's system comes from his full-backs and United's ability to stretch stubborn defences will rely on Valencia being able to get up and down the right wing. At 33, injuries are starting to become more and more frequent and his first job will be staying fit.

8. Luke Shaw (+4)

Ashley Young did well at left-back last season but a fully fit Shaw flying up and down the left would turn United into a different prospect. He made a good start against Leicester but needs to do it more often. He is yet to fully win over Mourinho but his team look more balanced when Shaw is in it.

9. Victor Lindelof (new entry)

The Swede had to wait for his turn last season but after a good World Cup he was picked ahead of Chris Smalling and Phil Jones for the first game against Leicester. He is gradually getting used to the physicality of the Premier League and is the best passer of Mourinho's centre-backs. Mourinho is expected to use him more regularly this season.

10. Fred (new entry)

There is already pressure on Fred because he is Mourinho's only key summer signing. How good he looks in United's midfield will depend on how quickly he adapts to English football -- it is not always easy for South American players in the Premier League, although Fred has the advantage of coming from Shakhtar Donetsk.

11. Marcus Rashford (-3)

No one has made more United appearances under Mourinho than Marcus Rashford -- it's just that not all of them have been from the start. The 20-year-old can expect a similar role this season, as first change behind Sanchez and Lukaku.

12. Ander Herrera (-1)

The Spaniard will face even more competition in midfield after Fred's arrival but he will still have a part to play. He has been particularly good in the big games and it would not be a surprise to see him picked against the top-six away from home.

13. Anthony Martial (no change)

The Frenchman scored in three consecutive Premier League games before Sanchez's arrival from Arsenal in January and then found himself on the sidelines. His pace and finishing ability make him a serious threat but a lot will depend on how focused he is on playing for United. He wanted out in the summer and will have to prove to Mourinho he can be trusted before he is thrown back into the team.

14. Juan Mata (no change)

Mourinho has plenty of options on the left of his front three but not so many on the right. Mata is not a natural winger by any stretch but he's got the ability to drift into pockets of space, which is a good quality to have against teams who are happy to sit back and defend.

15. Ashley Young (new entry)

Young cutting in from the left to cross with his right foot became one of the themes of United's attacking threat last season. He will battle Shaw to start at left-back and one of the notes in his pro-column will be his delivery into the box.