Al Ain maintained their perfect start to the western league phase with a fourth consecutive victory, strengthening their position at the top of the standings.
Al Ain stun Al Ittihad in Jeddah
Al Ain took control of the contest at Alinma Stadium, with Alejandro Romero, popularly known as Kaku, opening the scoring in the 17th minute.
Rafael Rodrigues doubled the visitors' advantage in the 42nd minute, giving Vladimir Ivic's side a comfortable 2-0 lead at half-time.
Al Ittihad responded after the break, with Marwan Al-Sahafi reducing the deficit in the 53rd minute to give the home supporters renewed hope.
However, the visitors restored their two-goal advantage five minutes later when Jan-Carlo Simic inadvertently turned Houssine Rahimi's effort into his own net.
Matias Palacios then converted a stoppage-time penalty to complete the 4-1 victory and hand Al Ain another important three points.
The result moved Al Ain to 12 points from four matches, keeping them at the summit of the western league standings. Al Ittihad, meanwhile, remained on four points.
João Félix inspires Al Nassr's 6-2 victory
In Tashkent, Al Nassr delivered an attacking masterclass to defeat Uzbekistan's Pakhtakor 6-2, with Portuguese forward João Félix playing a starring role.
Abdullah Al-Hamdan opened the scoring in the 15th minute before Félix doubled the advantage two minutes later.
The former Barcelona and Chelsea forward completed his brace in the 32nd minute to put Al Nassr firmly in control.
Pakhtakor pulled one back through Flamarion in the 36th minute, but the Saudi Arabian side maintained a 3-1 advantage at the interval.
Al Nassr continued their dominance after the restart, with Abdulelah Al-Amri heading home the fourth goal in the 53rd minute from Félix's corner.
Abdulrahman Ghareeb made it 5-1 in the 62nd minute before Dostonbek Khamdamov scored Pakhtakor's second in the 75th minute.
Angelo completed the scoring four minutes later to seal an emphatic 6-2 victory for Ange Postecoglou's side.
Cristiano Ronaldo was rested for the encounter, leaving Félix to lead the attack. The Portuguese forward finished with two goals and two assists.
The victory moved Al Nassr to six points from three matches, with their postponed meeting against Al-Wasl still to be rescheduled.
Other AFC Champions League Elite results
Elsewhere, defending champions Al Ahli were held to a goalless draw by Al Sadd in Qatar, while Iran's Tractor FC came from behind twice to secure a 2-2 draw against Uzbekistan's Neftchi.
Brendan Rodgers' Al Qadsiah recorded a commanding 5-0 victory over Al Gharafa, with Julián Quiñones scoring twice.
Al Wasl also claimed their first victory of the campaign after edging Iraq's Air Force Club 4-3 in an entertaining encounter.
The top eight teams in each of the western and eastern league-phase standings will advance to the knockout rounds.
Selected results:
• Al Ittihad 1-4 Al Ain
• Pakhtakor 2-6 Al Nassr
• Al Sadd 0-0 Al Ahli
• Tractor FC 2-2 Neftchi
• Al Gharafa 0-5 Al Qadsiah
• Al Wasl 4-3 Air Force Club