"This chapter is over," Ronaldo cryptically said on social media with a photo of him in an Al-Nassr shirt.
Ronaldo, the top scorer in this season's Saudi Pro League, has eight in seven appearances in this campaign's Champions League Elite, one short of joint-top scorers Riyad Mahrez, Salem Al-Dawsari, Anderson and Jasir Asani.
The 19-year-old forward, who trains daily alongside one of football’s all-time greats, is part of a promising Saudi Arabian generation aiming to make a statement on the global stage.
Al-Nassr remain in the third place with 54 points but they are now three points behind second-placed Al-Hilal and seven off leaders Al-Ittihad, who visit Al-Ahli on Saturday.
Cristiano Ronaldo's Saudi side Al Nassr were on Monday drawn against last season's runners-up Yokohama F-Marinos of Japan in the quarter-finals of the Asian Champions League.
Ronaldo, the Al Nassr captain, was reportedly rested for last week's goalless draw in the first leg in Iran, however returned to lead the side at Al Awwal Park.
Ronaldo turned 40 last week with his current contract due to end in June 2025.
Al Nassr captain Ronaldo had looked destined to endure a hugely frustrating game following a series of missed opportunities in the first half at Al Bayt Stadium.
The Portuguese star, without a goal in his past three appearances for the Saudi Arabian side, netted the second of the hosts' goals at Al Awwal Park in Riyadh.
Former Liverpool striker Sadio Mane and Anderson Talisca also scored for the Saudi side late Tuesday as they made it three wins from three in the group stages of the premier Asian club competition.
Senin Sebai scored on the break to put the club from Dushanbe in front with a minute left in the first half and Istiklol held out under relentless pressure until Ronaldo levelled with a clever clipped finish in the 66th minute.
Cristiano Ronaldo made the most of both awful defending and a plume of smoke to set Al-Nasr on the way to a 4-3 victory against Al-Ahli in the Saudi Pro League.
Cristiano Ronaldo enjoyed a winning debut in the Asian Champions League as he helped Al Nassr to a 2-0 victory against 10-man Persepolis in Iran on Tuesday night.
The streets were crowded with fans who raised welcome banners and pictures of Ronaldo upon the arrival of the Saudi Arabian team in Iran after the restoration of relations between the two countries
Five times UEFA Champions League winner Cristiano Ronaldo will begin his quest to add another continental title to his resume on Tuesday when Saudi Arabia's Al-Nassr kick off their Asian Champions League campaign against 2020 runners-up Persepolis.
Ronaldo scored his sixth goal in his last three games and claimed two assists as Al Nassr recorded a third straight league victory. Sadio Mane was also on the scoresheet.
Cristiano Ronaldo was named in Portugal's squad on Friday for upcoming Euro 2024 qualifiers against Slovakia and Luxembourg.
The Portuguese superstar got things underway in the 13th minute as he converted from the spot after a handball in the Al Shabab penalty area. He added to his tally five minutes later with a header only for the goal to be disallowed for a push on a defender.
Spain centre-back Laporte won 12 major honours during his successful spell with City
