Morocco coach Herve Renard conceded it will be difficult to stop Portugal's Cristiano Ronaldo when the two sides meet in Moscow on Wednesday.
Ronaldo scored the 51st hat-trick of his career as Portugal and Spain played out a thrilling 3-3 draw in their opening group game at the World Cup.
Morocco, who lost 1-0 to Iran after a 95th-minute own goal, face an early exit in their first finals appearance since 1998 unless they avoid defeat against the European champions.
"Even if you want to draw up plans for Ronaldo, he always finds a way out or makes a difference or puts him team back on the right track," Renard said on Tuesday.
"He's absolutely exceptional. Perhaps that word isn't even strong enough but you have to do everything to stop him."
Argentina's Lionel Messi was subdued by a collective effort by Iceland to frustrate the Barcelona star in a 1-1 draw, but Renard said Morocco could not afford to focus solely on the Portugal captain.
"If we put three people on Ronaldo I don't know how you'll be able to mark the other players," he said.
"They have so many attacking players. They are the European champions don't forget, and if I remember rightly, in the final against France he was injured and his team-mates made the difference."
Morocco progressed through the final round of African qualifying without conceding a single goal, but Renard admits Ronaldo and Portugal represent a considerable step up in class.
"Obviously he is a major player and together with Messi is one of the biggest stars in the competition."
"And if this is the last time in our life we play against Cristiano Ronaldo then we have to be as good as possible," he added.
"We'll have to be better than usual. As far as we are concerned in the last two-and-a-half years we've never competed against such a good team, so we'll have to do much more and be much better."
Morocco midfielder Nabil Dirar said the Atlas Lions are not thinking about anything but victory against Portugal, with their final Group B game against Spain on June 25.
"For us it's like a final," Dirar said. "Tomorrow will be a major battle for everyone. We know that the Moroccan people are behind us, we know we'll have a lot of fans with us tomorrow so we will give our all on the pitch.
"We don't want to draw, we'll do everything possible to win."
© 2018 AFP