Survival was on the line as both sides entered the match needing to win, preferably by a large margin, to stay in the hunt for one of the last eight spots in the Round of 32, but Graham Arnold's Iraq side wasn't up to that task.

Senegal struck in the fourth minute after Lamine Camara hooked a corner into the box and Abdoulaye Seck’s downward header grazed off the boot of team-mate Habib Diarra to send the ball up and over Iraq keeper Ahmed Basil.

More trouble followed for Iraq when defender Rebin Sulaka pulled Sadio Mane down on the edge of the box. After a video assistant referee (VAR) check for a possible red card, Sulaka was given his marching orders by English referee Anthony Taylor.

Australian Arnold said that "stupid" early red card made it even tougher for the team to perform against a top side like Senegal.

“With 11 men, it would have been hard enough as it was, let alone having 10 men for that long,” Arnold said.

Iraq, was making just its second appearance at a FIFA World Cup and its first in 40 years, but will go home without a point.

“It was an amazing experience, but I want to apologise [to] our fans, [to] our nations,” defender Merchas Doski said. “These three games, we didn't learn from our mistakes."

Despite being down a man, Arnold's Iraq was brave in attack in the first half and Senegal failed to capitalise on the advantage, with long-range efforts from Ismail Jakobs and Mane sailing wide.

It rained goals in the second half, however, as Senegal came out with more urgency and conviction.

Crystal Palace star Ismaila Sarr bagged his fourth career FIFA World Cup goal from close range to become his country's all-time leading scorer in the tournament and substitute Pape Gueye unleashed two rockets from distance to send Senegal’s army of fans into raptures.

Iliman Ndiaye added another long-range strike to cap off Senegal’s five-star performance, and their green-clad supporters began to chant “Senegal! Senegal!” as the clock wound down.

Senegal finished third in Group I with three points, behind France and Norway. Iraq finished fourth with zero points.

The African side must wait until the group stage ends on Sunday (AEST) to see if it is one of the eight best third-placed teams to advance to the Round of 32.