Liverpool manager Jurgen Klopp must prioritise the signing of a new holding midfielder in the summer to provide his back four defensive cover, former Reds midfielder Dietmar Hamann has said.
The Merseyside club strengthened their backline by signing Virgil van Dijk from Southampton for £75m ($106m) last month – a world-record fee for a defender.
Liverpool also have a deal in place with RB Leipzig that will see Guinea midfielder Naby Keita move to Anfield in the summer, but Hamann insisted that the Van Dijk and Keita signings alone would not fix the club's defensive issues.
The Reds have conceded 29 goals in their 25 Premier League games this season – the second-worst defensive record in the top six.
"[The defence has] been an issue for a long time," Hamann was quoted as saying by the Liverpool Echo.
"I think Van Dijk will improve them, I think he brings pace and a physical presence to the team but I think they lack a holding midfielder.
"I think they've lacked that holding midfielder for a while now so unless they bring in someone who really protects the back four.
"I think Van Dijk will improve them but not as much as I think they need to be improved to really challenge for titles on a consistent basis."
Liverpool are third in the Premier League table, two points above fifth-placed Tottenham, whom they face at Anfield on 4 February.
Klopp said in the build-up to the Spurs clash that achieving Champions League qualification for a second successive season was a more "realistic" target for his team.
"Being champion is probably the dream – not only at Liverpool but especially at Liverpool. Because of the season [Manchester] City is playing that is quite difficult. Then I would prefer to be second, to be honest, if you cannot be first," the German was reported as saying by Sky Sports.
"But if you are second, third or fourth at the end of the season when you look back all three positions are good and similarly difficult to reach."