The Reds have endured defensive difficulties this season, but offensively they are among the most exciting sides in Europe.
With the likes of Philippe Coutinho, Sadio Mane, Mohamed Salah and Roberto Firmino performing at the peak of their powers, Jurgen Klopp’s side are a joy to watch at times.
Manchester United legend Keane remains unimpressed, however, despite the Merseyside outfit having swept into the last-16 of the Champions League with a 7-0 mauling of Spartak Moscow.
“A comfortable night for them, a good start and their attacking players certainly enjoyed it,” the outspoken Irishman told ITV.
“But the big tests are yet to come for Liverpool.
“Clearly they’re beating these so-called lesser teams, and the same in the Premier League.
“But they’ve beaten nobody domestically and in Europe yet.”
Liverpool are now through to the knockout stage in continental competition and perched inside the Premier League’s top four.
Keane has, however, already suggested this season that he is not expecting much from the Reds.
He said after a 3-0 win over Maribor in early November: “If Liverpool were playing in my back garden, I wouldn’t watch them.
“They’re just drifting nowhere. They’re neat and tidy, but we know what they are like defensively.
“Come the end of the season when the prizes are being given out, Liverpool will be nowhere near.
“At the back, there are question marks over the goalkeeper and there’s not too much about to say them.”
Keane later shrugged off those comments as “tongue in cheek”, but his opinion of the Reds clearly has not improved despite their recent goalscoring exploits and nine-match unbeaten run.