Swansea City defender Angel Rangel says new signing Federico Fernandez needs to show he is worth his price tag.
Rangel said the 25-year-old, signed for a fee understood to be about £8m, will give the squad a boost.
"Now his job is to settle in quickly and prove his worth," he said.
The former Napoli defender joins on a four-year deal.
Fernandez made four starts for Argentina at the World Cup on their way to the final, where they were beaten by Germany.
He should be included in Swansea's squad to face Burnley in their first league game at the Liberty Stadium on Saturday, subject to international clearance.
"We've been able to sign a player like him, which is good for the Swans," said Rangel.
"I think he's going to adapt quickly and think he is going to be an important player for us."
Fernandez was on loan at Spanish La Liga side Getafe last season where he made 13 appearances, scoring one goal.
He said it was his dream to play in the Premier League and spoke to Michu and Jordi Amat before signing.
Fernandez joins a host of new faces in south Wales as boss Garry Monk made a number of signings in key positions during the summer.
Midfielder Gylfi Sigurdsson, 24, also signed for the Swans from Tottenham in July with Wales international Ben Davies going to Spurs.
Ecuador's World Cup winger Jefferson Montero was another addition.