Former England winger Chris Waddle has claimed that Liverpool's problems at the back could be exposed in the last-16 stage of the Champions League.
Jurgen Klopp's side smashed their way into the knockout rounds with a 7-0 victory over Spartak Moscow at Anfield on Wednesday night.
The result ensured that the Reds finished as Group E winners and they became the most prolific English club in the group phase of the competition.
Despite the team's impressive showing against Spartak, Waddle is concerned that Liverpool will have problems when they face better opponents in the next round.
"Liverpool can score goals and that's the hardest part of the game, but coming up against opposition their defence might struggle," Waddle told BBC Radio 5 live.
"You can still see Liverpool scoring but will they be strong enough at the back to deal with that quality? Liverpool are great on the eye but it starts to get hard now."
Liverpool are unbeaten in nine games in all competitions.
