The best chance for a Scotland win looks most likely in the first game against Haiti.
Ranked 84th in the world, the Carribean nation qualified for their first World Cup since 1974 by beating Nicaragua last month.
Manager Sebastien Migne has been unable to set foot on Haiti since being appointed 18 months ago because a conflict in the country forces them to play their home matches 500 miles away in Curacao – an island nation just off the coast of South American country Venezuela.
Wolves’ midfielder Jean-Ricner Bellegarde is among their squad, some of whom play in Major League Soccer or European leagues.
Morocco are second seeds but are ranked 11th in the world, were semi-finalists at the last World Cup and boast the likes of Paris Saint-Germain’s Achraf Hakimin and Real Madrid’s Brahim Diaz.
They won all eight of their qualifiers, scoring 22 goals and conceding just twice.
While Brazil stars like Vinicius Junior and Gabriel need little intorduction, nor does manager Carlo Ancelotti.
However, the five-time winners struggled in qualifying. They ended up fifth in the 10-team section in South America, losing six times, including to Bolivia.
So if Scotland can beat Haiti and either take a point or narrow defeat against the top two seeds, they stand a good chance of going through to the last 32.
Not that Clarke is taking anyone lightly.
“Haiti as the pot four team will be difficult,” he told BBC Scotland.
“They won their qualifying section quite comfortably but we managed to win ours as well so bring it on.”