Barcelona forward Lamine Yamal has said his angry response to being substituted against Alavés last weekend was due to frustration over his own performance.

Yamal, 17, was replaced in the 67th minute by Ansu Fati, by which point Barça already led 3-0 thanks to a Robert Lewandowski hat trick on their way to an eighth league win in nine games under new coach Hansi Flick.

The Spain international was visibly upset to be taken off, with Flick later asking him for the reason behind his reaction.

"More than anger it was because I was not happy with how I had played," Yamal told RNE in an interview from Spain's Madrid base ahead of this week's UEFA Nations League matches.

"I think I could have played better. I demand a lot from myself and that's the line I have to follow to be at 100% when I play.

"Yes, [I spoke with Flick after]. He asked why I was like that, if it was to do with being substituted. I told him no, it was because I could have helped the team more. I told him for the next game I would be at 100%."

Yamal, who starred as Spain won the European Championships in the summer, has started 10 of 11 games in all competitions for his club this season.

The only match he began on the bench was the defeat against Osasuna, when he came on to score one of the five goals he has netted this season. He also has five assists.

"We're enjoying ourselves a lot and it tells," he added when asked about Barça's impressive form under Flick. "We are happy with the style of play. Flick gives us confidence and freedom and we're happy to keep picking up three points.

"Physically we have to press more, but when you win the ball back quickly, the legs recover better. But it is true that the team is more physical than last year."

Yamal is not the only player shining under Flick, with strike partners Raphinha and Lewandowski also in fine form in the final third.

Raphinha has scored six goals and set up five more, while Lewandowski has scored 12 times in 11 appearances already.

"Every ball you give to [Lewandowski], he scores," Yamal said. "We're so happy for him. Hopefully he keeps going like this and ends up as the top scorer."

A year on from his international debut, Yamal now turns his attention back to Spain. He has already won 16 caps for his country, scoring three goals, and is preparing for the European champions' homecoming with fixtures against Denmark on Saturday and Serbia on Tuesday.

"We can't wait to play in front of our fans," he said. "[Winning the Euros] has generated a lot of excitement -- for them and for us.

"Going out every game and seeing people excited to watch me is special. All players grow when they see they have that support from the fans, which motivates me even more."