Liverpool manager Juergen Klopp is satisfied with his current defensive options and believes there are few centre backs in the transfer market who could improve his current squad ahead of the Premier League season.

Liverpool were hoping to add Virgil Van Dijk from Southampton but withdrew their interest in the Dutch centre back after Saints accused them of making an illegal approach.

Klopp is prepared to kick off the campaign with Ragnar Klavan and Joe Gomez providing backup to first-choice pairing of Dejan Lovren and Joel Matip at the heart of Liverpool's defence.

"Look out there and tell me five that would make us stronger. Five. Then you win a prize. It's difficult how it is," Klopp has told reporters.

"We have four. I don't think we need more. We cannot force the things and we would never get a centre back just because (of the sake of it).

"I'm happy. You can imagine we are still working on different things and we will see if it works. I am already here to work with this squad and not just always thinking 'but if we don't get this or this'."

Klopp was particularly impressed by a series of mature pre-season displays by left back Alberto Moreno, who struggled for form during the majority of last campaign.

"What I said is the truth. There is all this talking about signings and then you see Alberto Moreno - what a pre-season. You saw it. He has matured 100 per cent," Klopp added.

"Ryan Kent looked unbelievable, Dom (Solanke) - yes maybe a few guys expected that, maybe not. That’s cool and I cannot ignore it."

Liverpool open their league campaign on Saturday with a trip to Watford, three days before the first leg of their Champions League playoff at Hoffenheim.