Saudi Pro League champions Al-Hilal slipped to a shock 1-0 loss in the first leg of their Asian Champions League Elite last 16 clash with Uzbekistan's Pakhtakor in Tashkent on Tuesday after Brazilian Flamarion scored the only goal.
Meanwhile, Al-Ahli netted twice in four first-half minutes through Galeno and Riyad Mahrez on the way to a 3-1 win over Qatari hosts Al-Rayyan ahead of next week's return legs.
Pakhtakor squeezed into the knockout rounds with their first win of the league phase in the final round of fixtures and claimed a second victory by beating the four-times champions.
The winner came in the 29th minute when Brayan Riascos outmuscled Ali Al-Bulayhi on the right before whipping a low cross towards the six-yard box that Flamarion stroked first time into the bottom corner.
Al-Ahli boosted their hopes of a quarter-final place when Galeno, who joined from Porto in January, headed home Roberto Firmino's clipped cross from the right in the 30th minute.
Four minutes later the Jeddah-based outfit doubled their advantage when Mahrez crashed his shot into the roof of the Al-Rayyan net after Firmino rolled an indirect free-kick into his path from 12 metres.
Al-Rayyan's Roger Guedes ignited the tie with a curling shot from 20 metres into the top corner that beat goalkeeper Edouard Mendy with 19 minutes remaining and the Brazilian almost equalised in added time, thumping a shot against the crossbar.
The Qataris were to rue that miss as Feras Al-Brikan finished off a counterattack led by Mahrez five minutes into injury time and Al-Rayyan ended the game with 10 men when Adam Bareiro was sent off for a lunge on substitute Fahad Al-Rashidi.
Al-Hilal host Pakhtakor in Riyadh next week when Al-Ahli entertain Al-Rayyan with places on the line in the draw for the last eight, which will be held in Kuala Lumpur on March 17.
The competition's final stages will be a centralised format staged in Jeddah, with the quarter-finals on April 25 and 26. The semis are set for April 29 and 30 with the final on May 3.