Valencia, who had already had a third-minute header ruled out by VAR for offside, slotted in the tournament’s opening goal from the penalty spot in the 16th minute after being brought down by nervous-looking goalkeeper Saad Alsheeb.
He powered home a 31st-minute header for the second and the South Americans then cruised home as an outclassed Qatar struggled to mount any meaningful attacks and had only a fluffed header by Almoez Ali to show for their limited efforts.
The other teams in Group A, Senegal and the Netherlands, meet in one of three games on Monday.