Midfielder Pedri has lauded "sergeant" Hansi Flick after Barcelona's impressive start to the season, saying they are working harder than ever after winning their first four games in LaLiga.

Former Bayern Munich and Germany coach Flick replaced Xavi Hernández at the start of the summer and has guided Barça to wins against Valencia, Athletic Club, Rayo Vallecano and Real Valladolid going into the September international break.

Pedri, 21, says strength and fitness gained during a tough preseason is one of the big reasons Barça have flown out of the blocks.

"We work much harder than before," he told Mundo Deportivo. "The new fitness coaches that have come in are really good for us. We work hard and you notice it in the games.

"The team doesn't dip after the 70th or 80th minute, it maintains the same fitness levels. We [the Spain internationals] arrived late [after the European Championship], but speaking with those at preseason from the start, they were really put through it. A lot of strength work, a lot of physical exercises.

"When we arrived, there was another final push until the games started. Now with LaLiga underway it's a little different."

In addition to appointing Flick, Barça overhauled their fitness department this summer, with Julio Tous, who previously worked with Antonio Conte, among those coming in after president Joan Laporta demanded improvements.

Flick is also keen on physical preparation but, while he can be demanding, Pedri says he also has another unseen side to him.

"He's really close to the players; someone who likes to talk with us," Pedri added. "Apart from being serious, he also enjoys a joke, he's not always as serious as he appears.

"He helps us young players a lot. He's always on top of what we need and you appreciate that. When things have to be taken seriously, though, he does. He does have that element of [being a] sergeant about him, but he's as good as gold when he speaks with the players."

Pedri has made a good start to the campaign after recovering from an injury picked up at the Euros. He came off the bench in the opening day win at Valencia and has started the following three games, scoring the equaliser against Rayo as Barça came from behind to win.

"I feel free," Pedri said of his role under Flick. "I think that's what he has transmitted to me, to play without pressure and to do what I know. I feel much more at ease.

"Physically, I notice that I am doing much better, too, to be able to do different things. Flick is really good in that sense, giving us confidence.

"Now all I ask for this season is that injuries respect me and that I can help the team, because I think we have strengthened well."