Goals from Roger Ibanez, Ivan Toney, Galeno, Saleh Abu Al-Shamat and Ziyad Al-Johani sealed a comfortable win for Matthias Jaissle's side, who moved on to 13 points from six matches to guarantee a top-eight finish in the 12-team standings.
"We did well today and we go home with three points," Ibanez said. "That's the important part."
Ibanez gave Al Ahli the lead when he converted Toney's cut-back in the 30th minute and the former Brentford striker doubled the lead when he raced onto a pass through the middle by Galeno soon after the restart.
Galeno converted from a tight angle and Al Shamat and Al-Johani netted in the closing stages as Al Ahli bounced back from a surprise loss to Sharjah FC last month.
Al Ahli are joined in the next round by Tractor, who claimed a 2-1 win over Qatar's Al Duhail through a late goal by Amirhossein Hosseinzadeh.
Benjamin Bourigeaud had given Al Duhail a 35th-minute lead from the penalty spot but Shojae Khalilzadeh levelled the scores and Hosseinzadeh hit the winner two minutes into stoppage time.
Tractor moved on to 14 points and second in the table behind Al Hilal who recorded a sixth consecutive win in the competition with a 1-0 victory over Sharjah in the United Arab Emirates.
Simone Inzaghi's side had already confirmed their place in the next phase and picked up another three points when Malcom struck with nine minutes remaining.
Al Gharafa kept their qualification hopes alive through a 1-0 win over Al Wahda from the UAE with Seydou Sano scoring an 87th-minute winner for the Qatari side.
Al Gharafa climbed to six points and ninth in the table while Al-Wahda, who have qualified, dropped to fourth.
The first eight finishers in the league phases in East and West Asia advance to the round of 16, which will be played in March, with the quarter-finals, semi-finals and final in Saudi Arabia in April.