Morocco coach Walid Regragui has urged his team to believe they can defeat powerhouse Spain as they attempt to reach a first World Cup quarter-final.
The north African side are in the last 16 for only the second time after advancing as winners of Group F ahead of 2018 runners-up Croatia, having defeated Belgium and Canada in Qatar.
"That said, we've also got things up our sleeve. We've had one extra rest day compared to them and we're going to try and pull a surprise out of the bag.
"If we're able to send Spain packing I think this will be a wonderful surprise not only for us but for our country."
Spain denied Morocco a famous win at the 2018 World Cup with a last-gasp equaliser in a 2-2 draw, the only point the Moroccans picked up in Russia.
Morocco, the lone Arab nation and the last African team remaining in Qatar, will have the vocal backing of thousands of fans for Tuesday's game at Education City Stadium.
"We'll come out swinging. We want to hoist the Moroccan flag way up high. We're playing first and foremost for us and our country," said Regragui.
Morocco would become just the fourth African team to reach the quarter-finals -- after Cameroon in 1990, Senegal in 2002 and Ghana in 2010 -- if they beat the 2010 champions.
Morocco's only other appearance in the last 16 came in 1986, when they lost 1-0 to eventual runners-up West Germany.