Ronald Koeman says he needs time to make his mark at Barcelona as the Catalans attempt to bounce back from a Clasico defeat against Real Madrid when they meet Juventus in the Champions League on Wednesday.
Koeman's Barca kicked off the season with back-to-back wins, but they are without a victory in three games in La Liga now and have lost their last two.
The Dutch coach said he was never under any illusions about the scale of the task at Camp Nou, with a mini clear-out taking place after August's 8-2 loss to Bayern Munich in the Champions League.
"When I was in talks with Barca about becoming the coach, I knew it wasn't going to be an easy job," Koeman said in a news conference on Tuesday in Turin.
"Firstly because of the changes we wanted to make and secondly because of the situation with COVID-19 and the pandemic. It's a big challenge and I only ask calm and time because we're changing a lot of things."
Koeman's overseen the departures of Luis Suarez, Ivan Rakitic and Arturo Vidal, among others, and has turned to youth as Barca look to build for the future following their first trophy-less season since 2007-08.
Three teenagers started the weekend's defeat at Camp Nou against Madrid -- Sergino Dest, Ansu Fati and Pedri -- and despite the result Koeman saw plenty of positives.
"For 60 minutes against Madrid the team was very good," he said. "I respect everyone's opinion after Madrid's second goal. I think we were worse. But for the first hour, [with] the chances we had to take the lead, I saw a team with a lot of ambition."
Koeman will have to make changes for the game against Juve. Philippe Coutinho is injured and Gerard Pique is suspended. Marc-Andre ter Stegen and Samuel Umtiti remain sidelined, too.
"It's a big game, but not a decisive one," he said. "It's a match between two great teams that want to go far in this competition. Juve are at home but it's important that we get a good result playing the football we want."
Juve have selection problems of their own, with an injury crisis in defence and Cristiano Ronaldo's presence in attack dependent on the Portugal forward's latest coronavirus test coming back negative.
Koeman hopes that Ronaldo can play in what would be his first meeting with Lionel Messi since he left Madrid in 2018.
"Everyone wants to see the best players on the pitch," the Barca coach said. "I don't know if he's in condition to play, it's not my problem or my decision, but I hope he plays, for the game, for his fame... I respect him a lot."
Barca and Juve both won their first games in Group G. Barca beat Ferencvaros 5-1 at home and Juve won 2-0 away at Dynamo Kyiv.