Morocco held Croatia to a 0-0 draw in their opening game of the World Cup on Wednesday, producing a spirited display against the 2018 runners-up led by Luka Modric.

Backed by Qatar's large Moroccan community at the Al Bayt Stadium, the Atlas Lions followed up north African rivals Tunisia's strong performance against dark horses Denmark a day earlier to frustrate Croatia.

"This was an extremely difficult game," said Croatia captain Modric. "I do believe as the tournament goes on we'll be better and we'll adopt a more proactive attitude."

Modric insisted Croatia are capable of making another deep run despite a sluggish start in the early afternoon heat.

"We've not come here to just play and get out the group," said Modric.

"Our ambitions are a bit greater on the basis of our Russia achievement, but we need to take it one step at a time.

"Even before the 2018 World Cup we said our primary goal was to make it out the group. If we manage to do that we can be a dangerous opponent for any team."

Coach Zlatko Dalic had urged Croatia to exercise caution following Saudi Arabia's shock win over Argentina, a result Morocco captain Romain Saiss said had "opened the door" for the tournament's less-fancied teams.

Morocco took the game to a Croatia side featuring four players who started the 2018 final but struggled to create genuine chances against a defence marshalled by the experienced Dejan Lovren.

Azzedine Ounahi strangely opted against shooting when well placed inside the area, with Hakim Ziyech and Achraf Hakimi heavily involved down the right without ever truly threatening Croatia.

Ivan Perisic fired just over from distance for Croatia after intercepting a dreadful pass from Selim Amallah, while goalkeeper Yassine Bounou blocked well with his legs to deny Nikola Vlasic from close range.

Modric, the former Ballon d'Or winner appearing at his fourth World Cup at the age of 37, then hammered over from the edge of the box.

Morocco lost Noussair Mazraoui early in the second half after his diving header was saved, the Bayern Munich full-back injuring himself when he tumbled awkwardly to the ground.

Sofyan Amrabat poked Lovren's goal-bound effort away off the line after a scramble at a corner, while Hakimi's free-kick at the other end was beaten to safety by Croatian keeper Dominik Livakovic.

Only once have Morocco gone beyond the group stage, in 1986, but they will rate their chances of advancing with games to come against an ageing Belgium team and Group F outsiders Canada.

Croatia pushed for a late winner but found Morocco's defence in unforgiving mood as Walid Regragui's side secured a valuable and deserved point.

"I think it's a very good point for us," said Regragui, who was only appointed as Morocco coach in late August.

"It keeps us alive for the next two games. I'm very proud of my players. I think this game makes us more confident."