Saudi Arabia's Al-Ahli lost 1-0 to Sharjah FC from the UAE in Jeddah on Monday as the Asian Champions League Elite title holders suffered a rare defeat in front of their fans in the continental championship.
Ousmane Camara's 81st-minute strike handed Matthias Jaissle's heavily rotated side their first loss in this season's western league phase and the club's first defeat in the competition since April 2021.
Jaissle started with first-choice goalkeeper Edouard Mendy, midfielder Franck Kessie and England forward Ivan Toney on the bench and the champions were hit when Luanzinho released Camara to score the game's only goal.
The result leaves Al-Ahli in third place after five matches in the 12-team standings, two points behind leaders Al-Hilal, who face Iraq's Al-Shorta on Tuesday.
The first eight finishers will advance to the knockout rounds in March with the quarter-finals, semi-finals and final to be played in a centralised venue in Saudi Arabia in April.
Iran's Tractor FC moved up to second with a 1-0 win against Nasaf from Uzbekistan, Regi Lushkja scoring in Qarshi in the 17th minute with a first-time strike from outside the area to seal the points for Dragan Skocic's side.
Saudi Pro League champions Al-Ittihad were handed a 4-2 thrashing by Qatar's Al-Duhail as Algerian forward Adil Boulbina scored a hat-trick for Djamel Belmadi's side in Doha.
Boulbina drove home the opener in the fifth minute from 25 yards and the Algerian doubled his side's advantage with 12 minutes left in the first half, latching onto a through-ball by Marco Verratti before slotting past Predrag Rajkovic.
The 22-year-old completed his hat-trick eight minutes into the second half, the forward wrong-footing defender Jan Carlo Simic after being released into the penalty area by Luis Alberto to shoot under Rajkovic.
Krzysztof Piatek hit Al-Duhail's fourth with 16 minutes remaining with a powerful right-foot strike that left Al-Ittihad with little chance of staging a fightback.
Karim Benzema headed in two minutes later to give his side a glimmer of hope and the former Real Madrid striker bent in a fine second with seven minutes remaining, but it was not enough to deny the home side.
Shabab Al-Ahli from the UAE picked up their third win when first-half goals from Kauan Santos and Guilherme Bala sealed a 2-0 victory over Qatar's Al-Gharafa in Dubai.

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