Before Saturday, Marcus Rashford had played only 97 Premier League minutes this year, spread across five substitute appearances

England manager Gareth Southgate is right - Manchester United forward Marcus Rashford is a must for the World Cup.

Rashford showed why he has to be on the plane to Russia this summer with his performance in United's win over Liverpool on Saturday, when he scored twice in the first game he had started in the Premier League this year.

He has not been playing much recently, but United manager Jose Mourinho says Southgate has told him that does not matter and that Rashford will be in his squad this summer anyway.

I completely agree with him. Rashford is only 20, but he is ready now and he could make a big impact for England on the world stage.

'He is direct, he gets at people - and he can finish too'

One of the things Rashford does really well is carry the ball. England just don't have many players who can do that effectively.

His pace scares defenders and is another reason he is such a handful because he likes to take them on.

He is very direct, he gets at people and we know he can finish too - his first goal against Liverpool was brilliant.

Rashford showed great anticipation to run on to Romelu Lukaku's flick, then, when he got inside the Liverpool box, he did a little trick to wrong-foot Trent Alexander-Arnold and his finish was absolutely first class. Nobody saves shots like that.

His second goal involved a little bit of good fortune - but he still took his chance and that will boost his confidence further.

Rashford's second goal took a deflection off Trent Alexander-Arnold (number 66) on the way into the net. He now has 12 goals for United this season, surpassing his previous best of 11 from 2016-17.

Rashford looked a bit tired when he came off after 70 minutes, probably because he has not played 90 minutes very often - the last time he played a full game in the league was on 26 December, and there have only been two occasions in 2018 when he has played more than 45 minutes, both in the FA Cup.

Now he needs more minutes, not just for United but for England too. Southgate's side play the Netherlands and Italy in friendlies at the end of March and he definitely needs to be involved in one of those matches, if not both of them.

With 12 goals, Rashford has already scored more goals this season than any previous campaign, but he needs to carry on playing to keep his eye in, to continue trying to add to his goal tally and to keep taking people on.

'Rashford is not a player who gets rattled by very much'

The complaint is often made that England's players are never fresh going into a major finals. With Rashford, we actually want to see him used more in the next month or two.

If United progress in the Champions League and FA Cup next week, then Rashford could still end up playing a lot of games between now and the end of the season.

So he may well be tired at the end of May, but I always think with England that is more down to the pressure on our players than anything physical.

Rashford has started more than two successive games on only one occasion this season, back in September when he started the wins against Everton, Burton and Southampton in the Premier League and Carabao Cup. He has appeared in 27 of United's 30 league games in 2017-18, but 13 of those appearances have come off the bench.

Rashford does not strike me as the kind of player that gets rattled by very much anyway, which is another big positive considering his age.

I like the fact he stands up for himself too - if someone kicks him, he can handle himself and he does not seem very bothered by it.

His attitude is very good all-round. You only had to watch him against Liverpool to see him tackling back and helping his left-back Ashley Young, which shows he is a team player.

Discipline and hard work - Rashford does the job he is asked to do

I still think Rashford is a centre-forward rather than a winger, although he does a good job out wide.

I would love to see him play up front as part of a proper partnership because we got a glimpse of what could happen there with his movement off Lukaku for his first goal - but against Liverpool he did the job he was asked to do.

One of the reasons Rashford's game time has been limited recently is Alexis Sanchez's arrival from Arsenal in January.

Mourinho is still trying to find a place for Sanchez and, after trying him on the right and the left, he played him as a number 10 against Liverpool - to begin with anyway.

Juan Mata was on the right, and had a bit more licence to roam than Rashford did.

Rashford made 38 touches in total and scored with each of his two shots at goal, which both came from near the left-hand corner of the Liverpool area and were United's only shots on target in the game. He was replaced by Marouane Fellaini after 70 minutes.

Rashford basically stayed wide on his flank for the whole game while Mata came into the middle and wandered around.

While he might not have had the same freedom as Mata, Rashford still did an excellent job. He was very disciplined and worked hard in front of his full-back - and when he had the ball in the right areas at the right moments, he did the right thing.

He will surely have been disappointed to go off when he did because he had a chance of getting his first senior club hat-trick - but he can still look back on his performance and be very pleased.

Mata made 33 touches against Liverpool, but his involvement was not restricted to the right flank

United get a big week off to a strong start

Paul Pogba did not feature against Liverpool after getting injured in training on Friday, but I don't know how much difference he would have made to the game in the system United played.

When United were very deep in the second half, Pogba would have been sitting on top of his back four. Maybe he could have released Lukaku with some of those long balls we know he is capable of, but it was not the type of game that he could have taken control of.

Nobody should go home disappointed - Mourinho

Without Pogba, Mourinho's side ended up holding on for an important win, but we still don't know how he will fit his team together when everyone is available.

That is his headache, and it is a nice one for any coach to have - although it is frustrating for players who come in and out of the side.

I think it suits Mourinho, though. He thinks about each game - and the opposition's weakness - and picks teams to win them, unlike some managers who do not really change very much each week.

Although it is not always particularly entertaining, you cannot argue with the results.

Chris Waddle was speaking to BBC Sport's Chris Bevan.