Late Laporte header earns Al Nassr victory in Asian Champions League
The win moves the Riyadh-based club onto seven points from the opening three games, two points behind their table-topping compatriots Al Hilal and Al Ahli in the revamped continental club championship.
Al Wasl are a point further back after the side from the United Arab Emirates came from behind to defeat Qatar's Al-Gharafa 2-1 in Doha.
Ferjani Sassi had put the hosts in front a minute before the interval but Fabio Lima levelled with six minutes remaining and Isaac Success hit the winner two minutes into stoppage time to give Al Wasl their second win in three games.
In Dubai, Al Nassr were frustrated by a resolute Esteghlal team who had been forced to play the game on a neutral ground due to security concerns in Iran.
Goalkeeper Seyed Hossein Hosseini frustrated Stefano Pioli's team until the 81st minute, when he pushed Ronaldo's goal-bound header high into the air and Laporte rose to nod in the rebound.
The win puts Al Nassr in a strong position to advance to the knockout rounds of the competition, when the top eight finishers in the 12-team leagues in both east and west Asia advance.
The round of 16 will be played on a home-and-away basis in March while the quarter-finals, semi-final and final will be held as one-off matches in Saudi Arabia in April and May.