Al Ahli picked up their third victory of the campaign to move on to 10 points from the opening four rounds to sit in second place in the standings, two points behind their compatriots Al Hilal.
Riyad Mahrez put Mattias Jaissle's side in front in the 34th minute when the former Manchester City winger made the most of the home side's defensive deficiencies.
Al-Sadd midfielder Claudinho gave up possession deep inside his own half as the visitors pressed and the ball was worked to Enzo Millot, who set up Mahrez to place a clinical shot into the bottom corner beyond Meshaal Barsham.
Claudinho made amends in the 63rd minute when he fired into the top corner to pull the Qatari side level, but five minutes later, Matheus Goncalves's left-foot strike from a tight angle had too much power for Barsham to keep out.
Goals from Steven Bergwijn, Karim Benzema and Roger Fernandes earned Al Ittihad their victory over Sharjah from the United Arab Emirates in Jeddah as the Saudi champions completed back-to-back wins in the league phase.
Al Ittihad lost their opening two matches in a competition they last won in 2005, but Bergwijn gave them the perfect start with a well-placed header from 12 metres out in the eighth minute.
Benzema hit the second goal in the 66th minute when the former Real Madrid forward arrived unmarked in the penalty area to sidefoot in Moussa Diaby's centre from the left and Fernandes slid in to score the third four minutes into stoppage time.
The win moves Al Ittihad up to sixth in the standings, six points behind Al Hilal as the 12-team league phase in West Asia reaches the midway point.
The top eight finishers in both West and East Asia progress to the knockout rounds in March, with the quarter-finals, semi-finals and final to be played in Saudi Arabia in April.
