Both teams had already advanced to the knockout stage, but Nigeria avoided a meeting with Brazil by finishing first in Group D with nine points. Saudi Arabia was second with six points and will have to play the South American champion in the round of 16. Nigeria will meet England, which is playing the tournament without its top players.
Musa gave Nigeria the lead with a powerful right-footed shot from the top of the area after a perfect pass by Omoh Ojabu two minutes into first-half stoppage time. Kayode sealed the victory with a goal from inside the area in the 85th, controlling the ball before sending it past Saudi Arabia goalkeeper Abdullah Alsdairy.
Saudi Arabia threatened early and had two great chances from striker Yahya Dagriri. He fired a long-range shot that forced Nigeria keeper Dami Paul to make a difficult diving save to tip the ball wide in the 37th minute, then missed from near the penalty spot when he had only the goalkeeper to beat a minute into first-half injury time, just before Nigeria's goal.