Liverpool have completed the signing of 22-year-old Spanish left-back Alberto Moreno from Europa League champions Sevilla, the Premier League club announced on Saturday.

Liverpool did not disclose either the length of Moreno's contract or how much they paid to sign him, but British press reports put the transfer fee at around £12 million ($20.2 million, 15.1 million euros).

"In my view, Liverpool are the best club in England and I couldn't waste an opportunity to come and play for them," Moreno told the club website.

The Spain international completed the formalities of his move at Liverpool's Melwood training base, but he has not signed in time to feature in their Premier League opener at home to Southampton on Sunday.

"I spoke with (former Liverpool players) Xabi Alonso, Pepe Reina and Alvaro Arbeloa and they told me this is a spectacular club whose fans follow it in a very special way," Moreno added.

"They all told me I can grow a lot here as a footballer as this is a massive club. I'm very happy to be joining a club as big as Liverpool. I hope to give my best and do all I can to help."

Moreno, who bade a tearful farewell to Sevilla's fans after their 2-0 loss to Real Madrid in the UEFA Super Cup in Cardiff on Tuesday, becomes Liverpool's eighth close-season signing.

The Seville-born defender graduated from Sevilla's youth academy and made his first-team debut in April 2012. He has won three caps for Spain, but was not included in their World Cup squad.

He will compete with 28-year-old compatriot Jose Enrique and home-grown academy graduate Jon Flanagan for a place on the left flank of manager Brendan Rodgers's defence.