Paul Parker: Mohamed Salah is a sensation for Liverpool, but don't forget Roberto Firmino

When you look at Liverpool, with Mohamed Salah scoring a huge amount of goals, of course it makes a huge difference. It doesn’t matter how a player performs in general, if they score a goal their rating improves automatically by 50 per cent.

As a defender, I couldn’t stand goalscorers – sometimes because they came off the pitch and their shorts were all nice and clean and they had nothing on their shirt to suggest they had been in a battle. But they are the ones that get you a win bonus, because they make the difference at the other end.

With Salah he’s not a regular goalscorer – like Michael Owen – there is much more to his game. But he still needs a good foil, and he's got a brilliant one in Roberto Firmino. The Brazilian is not the quickest, yet he is very unselfish and will run for the entire match – in attack and defence – and divert defenders away from Salah to give him more room.

Many supporters may not see what he puts in – but if you went to speak to Salah or the Liverpool coaches you’d look at his strengths and a lot of them stem from the unselfish work that is done by his team-mate.

And yet Firmino is not really a centre forward, or a midfield player – in fact I’d like Jurgen Klopp to tell us how he would refer to him! We need to think of something better than a ‘false 9’ – we are going back several years to Barcelona with that analogy. We need to find a new term for him, as he does more than that term suggests.

He can be up there, on the last defender, playing with his back to goal, and isn’t scared of taking a kick either, like an old-school target man. Yet he also tracks back too when his team loses the ball, which fits in well with Klopp's pressing style. Finally, of course, he scores goals and creates them too – 10 strikes, and seven assists, in the Champions League so far attest to that. To put that in perspective, he's second in the goalscorers' table, equal with Salah and five behind Cristiano Ronaldo. Crucially, being such a threat on his own keeps defenders and midfielders busy so Salah can have more space when he cuts inside.

It makes a huge difference to Liverpool. However, the balance changes when one of those front three is not there. When Salah is absent, the other two – Firmino and Sadio Mane are not the same. It’s a bit like the MSN at Barcelona: Messi, Suarez and Neymar. When they were together it was incredible, but take Messi away and the other two aren’t as strong.

As for Roma’s defence, I have no idea what they were thinking about, setting up like that. The TV cameras kept zooming in on their coach, Eusebio di Francesco, and he looked a bit clueless. Having said that, the fact that the players were coming across to speak to him a lot is not such a big deal. Ashley Young is forever walking across to Jose Mourinho at Manchester United, so players speaking to their coach doesn’t bear any relevance. But looking at him in isolation, he was scratching his head and didn’t look like he knew what his intentions were.

I think Roma wanted to condense the game and allow Liverpool less time on the ball to pick their passes. And it worked for the first 30 minutes or so. But they didn’t have the personnel to do it all match – their defenders were not quick enough and they were not good enough in midfield to close Liverpool down and squeeze the game for 90 minutes.

I don’t think Trent Alexander-Arnold is ready to go to a World Cup. Looking at his game, when I’ve seen him, he’s been OK. But he's 19 and I just don’t think he has the experience.

Having said that, stranger things have happened. There are always late bolters, players who are thought to be out of the frame that make a late bid. I went to the World Cup in 1990, but did people think I was ready to go? I got the nod and ended up playing six out of the seven games in Italy. So it can happen.

I think it’s more about him playing for Liverpool – the team that everyone is talking about at the minute - so it’s easy to throw him in there because he’s English. He can still give the ball away a lot in Champions League football and he’s got a lot of competition for that right-back/wing-back spot.

And who would you leave out? There’s Kyle Walker and Kieran Trippier and you wouldn’t drop either of them ahead of Alexander-Arnold. They are currently better than him, more experienced and more adept at going forward. So Russia might come a bit too soon.