The Atlas Lions topped Group F with seven points from a possible nine to set up a tie with the 2010 champions, who could only place second behind Japan in Group E.
It would not be a surprise to see Regragui stick with the same XI that got the job done against Canada on the final day, where Yassine Bounou was back in goal after feeling unwell prior to the win over Belgium.
The Sevilla man came through the match against Canada unscathed and will expect to be protected by Romain Saiss and Nayef Aguerd, the latter of whom scored an inconsequential own goal against the Canucks.
Achraf Hakimi has been dealing with some ankle discomfort, but the Paris Saint-Germain defender is expected to be fit to take his place on the right as Noussair Mazraoui lines up on the opposite side.
Amid links with a move away from Fiorentina, all eyes will be on Sofyan Amrabat in the middle of the park, where he should be joined by Angers' Azzedine Ounahi and Sampdoria's Abdelhamid Sabiri.
Hakim Ziyech and Youssef En-Nesyri were both on target in the win over Canada, and the pair will expect to join Sofiane Boufal in the final third against the Spaniards.
En-Nesyri has now bagged two goals at the World Cup, and the Sevilla attacker could now become the first man to score three World Cup goals for Morocco should he find the net here.
Morocco possible starting lineup: Bono; Hakimi, Saiss, Aguerd, Mazraoui; Ounahi, Amrabat, Sabiri; Ziyech, En-Nesyri, Boufal