Steven Bergwijn's last-gasp winner earned Al-Ittihad a huge victory in their quest for the Saudi Pro League title, beating Al-Nassr 2-1 at King Abdullah Sports City on Friday.
Karim Benzema had given the hosts a 55th-minute lead before Cristiano Ronaldo levelled two minutes later, but Bergwijn struck the decisive blow in second half stoppage time.
In a tepid opening 45 minutes, clear-cut chances were hard to come by, with Bergwijn and Benzema going closest for the hosts, but unable to trouble Bento.
However, Al-Ittihad got themselves in front shortly after the break when Muhannad Al Shanqiti picked out Benzema, with the Frenchman on hand to tuck the ball home.
But the hosts' joy was short-lived after Angelo saw his effort cleared off the line by Danilo Pereira, before the Brazilian laid the ball back to Ronaldo to level the scoring.
With the game looking to end all square, Al-Ittihad stole the three points at the death as Bergwijn cut inside before curling a right-footed effort into the far-left corner.
The result moved Al-Ittihad three points clear at the summit, though Al-Hilal can go level with them with a win over Al-Raed on Saturday. Al-Nassr, meanwhile, stayed in fourth.
Data Debrief: Bergwijn bursts Ronaldo's bubble
Al-Ittihad have often been second best in their encounters with Al-Nassr, but they earned an impressive victory against Ronaldo's side, though it may not have been deserved.
They managed an expected goals (xG) total of just 0.66 from their 11 shots compared to Al-Nassr's 1.2 from the same number of attempts.
Benzema also ended his goal drought against Al-Nassr, having failed to score against them in his previous game against them. The former Madrid striker ended the game with a team-high xG of 0.36, while also having more shots (seven) and touches in the opposition box (four) than any of his team-mates.
Al-Ittihad have now won their last nine league matches, their second-longest streak in the competition after 10 wins between October 2021 and February 2022, while also triumphing in their eighth-straight home match in the Pro League.