Albert Celades has been impressed by Dani Parejo's positive response to what he acknowledged has been a difficult situation at Valencia.
Celades was brought in as Valencia's new coach following the dismissal of Marcelino – who guided them to two successive top-four finishes in LaLiga, along with a Copa del Rey triumph last season.
Defending champions Barcelona are first up for Celades, who was previously an assistant under Julen Lopetegui for both Spain and Real Madrid.
Valencia captain Parejo was among the players to take to social media in the wake of Marcelino's sacking, paying tribute to their former coach.
However, the Spain international posted a follow-up tweet on Thursday, stating: "Without excuses, with enthusiasm and with the maximum commitment. We are Valencia and we must live up to the badge."
It is a response that has pleased Celades, who says the players have shown a fantastic attitude despite the departure of a coach who was well respected by the squad.
"Under the circumstances that they have been through, the players have shown great professionalism," Celades told a news conference.
"Parejo is our captain. He's not just a player but also somebody very important for the fans.
"He's spent many years here, in very different times, and gone through many difficult situations as well as other nicer ones.
"He knows the club well and his attitude is very positive for all of us. I think it's a great show of responsibility.
"That's the way we want everybody to be. I hope that his optimism and mentality as captain is contagious."
Valencia drew both of their league meetings with Barca last term, before beating the Blaugrana 2-1 in the Copa del Rey final – a win that Marcelino believes played a part in him losing his job – and Ernesto Valverde is expecting a stern challenge despite the upheaval at Mestalla.
"I imagine it will be a similar kind of game even though they have changed manager," Barca's coach told a news conference.
"It was only two days ago. I don't really think there has been time, I'm sure there will be changes in time but it hasn't been enough.
"It's a team that has given us problems on the counter-attack, keep their lines together, quick on the break and can score from the smallest of chances, we saw that in the cup final.
"They're a Champions League team so we expect a Champions League kind of game."