Jurgen Klopp says Liverpool's Premier League title rivals Manchester City can win the quadruple, adding Pep Guardiola's side look like the best team in the world.
City moved back to the top of the table, a point ahead of Liverpool, thanks to a comfortable 2-0 home win against struggling Cardiff City on Wednesday.
Since their shock 2-1 loss away to Newcastle United at the end of January, City have hit top gear, winning eight games in a row in the Premier League, conceding just twice in that sequence.
Guardiola's side have also lifted the Carabao Cup during that run, beating Chelsea on penalties at Wembley, to take the first step towards a historic quadruple.