Barcelona head coach Xavi has hit back at "silly" criticism about Gavi's perceived overly physical playing style and told the midfielder to show even more passion.

The 18-year-old has featured in all 17 of league-leading Barcelona's LaLiga fixtures this season, starting 12 of those.

Gavi leads the way among Barca players for fouls conceded this campaign with 41 – at least 22 more than any other team-mate and the third-highest tally in the division.

He also tops the list in terms of duels contested (146) among Barca players and is behind only Sergio Busquets (1.73) for tackles per game with 1.65.

Some have suggested Gavi too often gets away with bad challenges, having been cautioned only three times, but Barca head coach Xavi does not agree with that assessment.

"That seems silly to me. There is a referee who decides, right? In the end, he is the one who decides," Xavi told reporters. "Gavi puts passion and courage into his game.

"I consider it that the whistle is blown for very few fouls on him. For me, it's the other way around. He's a player who's fouled a lot and the whistle is blown for a few of them."

Gavi's playing style has earned comparisons to Brazil international Casemiro, who won 18 trophies in nine years at Real Madrid prior to joining Manchester United last August.

But Xavi feels the young midfielder is only praised when representing Spain, rather than when putting on the Blaugrana strip.

"It seems to me that when he goes to the [Spanish] national team he is wonderful, and when he plays for Barca, he crosses the line," Xavi said.

"This is what it seems to me from the outside, yes. He's an example of grit and courage [for Spain] and, when he's at Barca, he is not liked, right?

"Well, it's normal. It is normal. And on top of that, if we win, he is liked even less. It is the way that it is.

"To Gavi, I say be calm, to put in the same passion, or even more, and also more courage and sacrifice... and that he doesn't stop. He doesn't have to slow down."

Gavi is in line to feature when Barca host Real Sociedad – who are third in LaLiga – in the quarter-finals of the Copa del Rey on Wednesday.

"It's a key match for us," Xavi added at Tuesday's pre-match press conference. "It's a quarter-final and a one-off match. We're playing in front of 80,000 of our fans.

"We are in good form and they are in a good moment also in terms of results and confidence. I expect we'll see a good game."