The Manchester United forward scored twice in the dying minutes to move to 111 international goals as Portugal came from behind to beat the Republic of Ireland 2-1 in World Cup qualifying on Wednesday
Ronaldo, the five-time Ballon d'Or winner has now scored 111 international goals and is now leading the charts.
Ronaldo, 36, can break former Iran forward Ali Daei's international scoring record of 109 with a goal in World Cup qualifiers against the Republic of Ireland and Azerbaijan.
Portugal national football team coach Fernando Santos said Ronaldo left Juventus' practice session with an arm issue on Wednesday but should be fit to join the national team.
Cristiano Ronaldo capped a lackluster season in Portugal’s 1-0 loss to Belgium in the round of 16 at Euro 2020.
Portugal has suffered an untimely blow with left-back Joao Cancelo withdrawing from Euro 2020, after testing positive for COVID-19.
FIFA World Cup 2018: Portugal captain Cristiano Ronaldo deserved red for elbow, says Iran coach Queiroz
Iran coach Carlos Queiroz said Portugal captain Cristiano Ronaldo should have been sent off for an elbow during Monday's 1-1 draw at the World Cup.
Spain and Portugal need draws to qualify while Russia will bid for a third straight win after a stunning start to the tournament.
He said the Portugal match is the most interesting and important clash for him in his seven-year career.
Portugal star Cristiano Ronaldo's fourth-minute header clinched a 1-0 victory over Group B opponents Morocco in Moscow.
Portugal will now face Iran in their final group game on June 25 in Saransk.
Ronaldo's hat-trick against Spain was the 51st of his career, many of which were scored alongside former Real centre-back Pepe who spent a decade at the Spanish giants.
Ronaldo's treble was the 51st in World Cup history and saw him become just the fourth player to score at four different editions of the tournament.
Santos is clear in his belief that Portugal will not be caught out by any surprise Spanish tactics following the last-minute upheaval.
The 33-year-old will lock horns with six of his Real Madrid team-mates as the Spaniards try to repeat 2010.