Cristiano Ronaldo played a pivotal role in keeping Al-Nassr's Saudi Arabian title aspirations alive, as he sealed a remarkable come-from-behind 3-2 triumph over Al-Shabab on Tuesday with a stunning winning goal.

If second-place Al-Nassr had lost the Riyadh derby then leader Al-Ittihad, which beat Al-Batin 1-0 earlier, would have been crowned champion with two games of the season remaining.

Cristian Guanca scored twice for Al-Shabab before Anderson Talisca of Brazil pulled a goal back for Al-Nassr just before the break.

Six minutes after the restart, the nine-time champions were level as Abdulrahman Ghareeb made it 2-2 from close range.

Just before the hour, Ronaldo put Al-Nassr ahead in style, sprinting past two defenders to curl a shot into the top corner from the edge of the area. It was the Portugal star's 14th goal since joining after the World Cup.

"To be 2-0 down is very difficult but we believed until the end and scored three goals; so congratulations to the team and the supporters who were amazing today," the former Real Madrid star said.

Al-Ittihad is three points clear at the top of the standings.

Ronaldo said the Saudi league is slowly improving, "Step-by step I think this league will be in the top five leagues in the world but they need time, they need players, they need infrastructure."