Diaz shines for Liverpool in FA Cup debut

Liverpool's new Stg 37.5million ($A72 million) signing Luis Diaz has given Anfield a glimpse of what he can offer with an encouraging 30-minute cameo in Liverpool's 3-1 FA Cup fourth-round win over Cardiff.

The Colombia international only met his teammates for the first time on Friday having waited in Paris most of the week for his visa to come through following his move from Porto last Sunday.

But Diaz was not lacking in determination nor invention as he played a significant role on Sunday in the decisive second goal for Takumi Minamino, after Diogo Jota's 15th of the season had given Liverpool the breakthrough in the 53rd minute.

Not to be outdone in Liverpool's surging second-half display, 18-year-old Harvey Elliott then announced his return after five months out with an ankle fracture dislocation with a brilliant swivelled finish in front of the Kop - his first goal for the club.

Cardiff substitute Rubin Colwill scored an 80th-minute consolation for the visitors with a smart finish past Kelleher but a place in the last 16 for only the second time in Jurgen Klopp's reign was never in doubt.

The only concern for Liverpool, who'll play Norwich at home in the next round, came late on when Diaz went down holding his knee after Cardiff captain Aden Flint accidentally landed on him - but the 25-year-old was able to finish the game after treatment.

A late run out for midfielder Thiago Alcantara, after six weeks out with a hip problem, was also encouraging for the Reds.

And with Africa Cup of Nations finalists Mohamed Salah and Sadio Mane due back before Thursday's Premier League visit of Leicester, Liverpool's challenge in four competitions is looking as strong as it has all season.