While Alexis Sanchez's 68th-minute strike was enough to hand the Catalan giants a 1-0 victory over city rivals Espanyol on Friday, Messi failed to score for the third game in a row.

As Sanchez's golden run in front of goal continued - the Chilean has now scored eight goals in seven matches in all competitions, Messi's poor form has attracted plenty of questions, although Martino remains unconcerned.

"I keep saying the same thing, I keep having to do an exclusive analysis of him (Messi) in every game," Martino said.

"He is the most important player in a team full of amazing players. He plays in his own way and offers us what he offers.

"If we keep winning, we will see the best of all of our footballers very soon."

Messi appeared to cut a forlorn figure after the match but Martino denied the Argentine was down on confidence.

"I don't think he's worried. In reality, I've seen him make the same facial expressions throughout his career. It's just a coincidence," Martino said.

"In the same way it was strange to see him score in 19 consecutive games (last season) it's also strange he hasn't scored in three games.

"Of course he would have been delighted to keep scoring two, three or four goals per game.

"He set the bar so high that now it seems as if there is a problem. But in my opinion, there's no problem."

Match-winner Sanchez added of Messi: "Leo is in the same form as always.

"He hasn't been scoring goals but he has provided assists, he has been taking on players.

"We think he's the same as always, playing very well."

It was far from a vintage performance from Barcelona but Martino was content with the way his side were able to grind out a win despite being below their best.

"In games like this you will always create chances because your opponents have run so much and they become tired," the 50-year-old said.

"We were imprecise in the final pass but we played the game the correct way, winning well against a team that did an impeccable job in defence.

"We looked to move the ball around, play triangle passes, while also playing long passes up the field. I don't think we lacked intensity when it came to attacking but we did lack continuity in pressing."