Van Dijk allows Liverpool to play with a high line, and be aggressive in the way they play, because of his speed and strength together with his quality in the air and in one-on-one situations.

The team are less gung-ho under Slot than they were in the last couple of seasons under Jurgen Klopp, and now they tend to only flood players forward when they know they have got a better foundation in behind, if they do lose the ball.

Even so, Van Dijk can still get dragged out of position sometimes when their back four is unbalanced - for example when Alexander-Arnold goes into midfield and Ibrahima Konate has to shift across.

But he always looks comfortable - and it appears almost effortless when he deals with whatever situation he is put in.

He's the biggest reason Liverpool can attack and pour forward with confidence, knowing they are not leaving the door open behind them.

Van Dijk makes it all look very easy and is extremely consistent too, so when he has a couple of shaky games, or even just difficult moments in games like he had against Everton and Fulham at the beginning of April, you always notice, but I always expect a big response to any mistakes.

When people talk about the best centre-backs of the Premier League era, he is obviously right up there.

If you could genetically engineer the perfect defender then you would build Van Dijk because on top of his physicality he can pass the ball brilliantly to launch attacks, and has this calmness about him too.

We often talk about when a player has composure on the ball, but what is special about Van Dijk is how composed he looks without it, because of his positioning and anticipation.

The barometer of an elite-level centre-back is whether they are in control of the striker they are facing, or vice versa.

It's very rare that Van Dijk is not in control, in any game, and he gives Liverpool the platform to dominate their opponents.

Salah has thrived under Slot and the way Liverpool play now definitely suits him, and makes him harder to stop.

One of the tweaks Slot made from Liverpool's playing style under Klopp was to add an extra attacker, and now we see Dominik Szoboszlai playing high up the pitch in a 4-2-3-1 formation.

It means more defenders are drawn towards the other players, and that gives Salah more space than he had in Klopp's 4-3-3 shape.

As a former full-back myself, I know the last thing you want in that position when you are facing him - and Luis Diaz or Cody Gakpo on Liverpool's left - is to be isolated in a one-versus-one situation with them.

When they are narrower, they are running inside into more bodies and have less of an effect on the game, but this season Salah is being asked to stay very high and wide.

That's partly down to Szoboszlai almost playing like a false striker, because Salah doesn't want to congest that central space too much, but his incredible numbers this season show how the system works.

He has been quieter of late - his assist for Luis Diaz's goal against West Ham on Sunday was his first goal or assist, other than penalties, since the end of February - but even during this spell where his form has dipped, you can tell Slot is reluctant to take him off because he knows if something falls for Salah, then more often than not he is going to convert it.

What is going to be interesting is the relationship he has with the right-back next season, whether it is Trent Alexander-Arnold or Conor Bradley.

Whoever plays in that role will know that Salah is not going to track back as much as he once did, which adds to their defensive responsibilities. And if the right-back is still getting forward as well, it means one of the centre midfielders and the right-sided centre-back will have to get across to cover more often.

Alexander-Arnold's future is still uncertain and his exit would affect the whole team, but it would have implications for Salah, in particular, given the phenomenal dynamic they have down the right.

If he leaves, Salah is going to lose some of his supply line for chances too.

I look back at the first game under Slot, at Ipswich last August, when Alexander-Arnold plays that ball behind the defence for Salah to run on to and set up Diogo Jota. It looks so easy, but it's not.

Some people pointed at the run of games in March and April where Salah did not perform well and put it down to his age - he turns 33 in June - but I don't see that as a factor.

Like Van Dijk, who turns 34 in July, he has started every Premier League game this season, so durability is not an issue.

You can see the condition Salah is in from his social media posts, but you only understand why he is in such fantastic shape when you hear his team-mates speak about his approach to training.

I've listened to interviews with Harvey Elliott and Curtis Jones where they talk about how Salah is always first at the training ground and how hard he works during sessions and in the gym.

So it is not a fluke that he is able to play all these games. He is prepared to put in the work off the pitch.

It is exactly the same with Van Dijk, and it shows their professionalism as well as their hunger for success. They have both won it all with Liverpool but they still want more.

We will probably see both of them rotated more next season, especially Salah, and they will obviously need replacing at some point - but it must be a huge relief to Slot to know that time has not come yet.

It looks as if Slot is going to win the Premier League in his first season, although until last weekend's results I actually was not too confident about that, despite Liverpool's lead at the top of the table.

The team have looked exhausted in recent weeks, with lack of rotation one of the reasons for that.

It felt as if there was far more trust in the squad in the first half of the campaign. Since then, Slot has almost reverted to a certain team and they are starting to look a bit tired, and far more vulnerable.

I am certainly not criticising Slot, because to do what he has done with a team he has inherited is still incredible, but I feel he knows he needs to strengthen and that we will see the difference next season when he has the squad depth he wants.

Even when Liverpool have looked heavy-legged, Slot has hardly given a sniff to Elliott or Federico Chiesa in midfield or up front. He either doesn't trust them, or feels they are not suited to his system.

It's the same with Jarell Quansah. He was on the bench against Fulham but, when Konate came off, Ryan Gravenberch dropped back to centre-half instead.

Whatever the reason, it feels almost a case where Slot is getting across the line using this squad this season, and there are going to be wholesale changes in the summer.

It makes what he has done in such a short space of time even more impressive, especially handling the contract issues of three of his biggest stars at the same time too.

Stephen Warnock was speaking to BBC Sport's Chris Bevan.