Ronald Koeman admits Lionel Messi's form "could be better" but insists he has no complaints about the Barcelona captain's application.

Messi attempted to leave the club during the transfer window but was unable to engineer an exit after something of a power struggle played out in public with president Josep Maria Bartomeu.

He has since affirmed his commitment to the Catalans for at least the final year of his contract, but his performances have not been up to his usual standards in 2020-21.

In four LaLiga matches, Messi has scored just once - a penalty in the 4-0 win over Villarreal last month - and has zero assists.

He has created just six chances, well short of the league-leading numbers of David Ferreiro (22), and only five from open play, eight fewer than Sevilla's Jesus Navas (13).

With 11 dribbles completed from 19 attempts, Messi has a success rate of 57.9, well down on last season's average of 64.3, which further highlights his relative struggle to impact upon Barca's play - a problem that came to a head in their 1-0 loss to Getafe.

However, speaking ahead of their first Champions League group game against Ferencvaros, Koeman made it clear he is happy with Messi's efforts and believes the player himself is feeling positive.

"There is always pressure to win games as a player or coach at Barcelona. We know the club's situation; there are things outside the pitch that we can't influence," he said on Monday.

"What we can do is work with the players to adjust to the new system and we have a lot of new and young people, but we're optimistic about the game tomorrow. I think the best way to think right now is game by game.

"Maybe Messi's form could be better at this moment, but he's happy, he's training well, he's focused, he wants to play and he wants to be captain of the team and he's improving. I haven't got any complaints.

"He also had bad luck with the ball that hit the post and with the final play of the match. Normally, he puts it between the posts! I have no doubt about his form and we'll see that in the coming games.

"I'm not worried because we've scored eight goals in four games and I don't think many teams have done that. It's normal that, against Sevilla and Getafe, it's more difficult to create chances.

"I'm not disappointed with the players. I see a happy team. I can never be disappointed with a player who works their hardest."

Given Barca's 8-2 humiliation at the hands of Bayern Munich in last season's quarter-finals, Koeman accepts his side are unlikely to be considered firm favourites for this term's trophy.

However, he is keen to get their campaign off to a strong start in a week that ends with the first Clasico of the season at Camp Nou.

"We know that, with what happened last time, we're not the ultimate favourites, but we can go far," he said. "You always play to win games and trophies at Barca, in Spain and in Europe, but there are more favourite teams, like us.

"We want to start the Champions League on the right foot. The most important thing is to prepare for two difficult matches at home that we have to win.

"It's not an easy game and we don't think about resting people for Saturday because Saturday isn't important right now, only tomorrow is."