The Teranga Lions secured their place in the last 32 as one of the best third-placed teams following an impressive performance.
Habib Diarra opened the scoring in the fourth minute, finishing after Abdoulaye Seck headed a corner towards goal.
Iraq were reduced to ten men soon after when Rebin Sulaka was sent off for denying Sadio Mane a clear goalscoring opportunity.
Senegal controlled the remainder of the match, scoring four times in the second half through a brace from Pape Gueye, along with goals from Ismaila Sarr and Iliman Ndiaye in a commanding display.
“We won 5-0, and I think it was well deserved. The team handled this match well,” Thiaw told FIFA website.
“It wasn’t easy at first because we were playing against a direct rival who wanted this victory too. Our future is no longer in our own hands. We will have to wait and see. But we got the job done.”