Riyad Mahrez scored twice late in the game to complete Al Ahli's victory over Qatar's Al Rayyan, the former Manchester City winger netting in the 77th and 83rd minutes to earn a 2-0 win in Jeddah and a 5-1 victory overall.
Al Hilal bounced back from a 1-0 loss in the first leg in Tashkent last week to secure a 4-1 aggregate success over Pedro Moreira's Pakhtakor side with a commanding performance at the Kingdom Arena in Riyadh.
The hosts pulled level on aggregate in the 31st minute through Hamad Al Yami's diving header after Salem Al-Dawsari's backheel released Mohamed Kanno behind the defence and his cross to the far post was directed home.
Eleven minutes later the Saudis doubled their tally as Kanno charged through Pakhtakor's midfield from deep inside his own half to deliver a defence-splitting pass from which Malcom slid his shot beyond goalkeeper Jhonatan.
Yassine Bounou denied Pakhtakor striker Flamarion with a reflex save early in the second half and that was to prove decisive as Al-Dawsari struck from the penalty spot in the 51st minute, scoring after being upended by Khodjiakbar Alijonov.
Nasser Al-Dawsari rolled the ball in from close range in the 92nd minute to complete the rout.
Victory takes Al Hilal into Monday's draw for the final stages of the competition, which will be played in a centralised format in Jeddah from April 25th until May 3rd.
"We just wanted to win so bad, for the supporters, for everybody, for us," said Al Hilal defender Kalidou Koulibaly.
"We knew that the first game was difficult in difficult conditions but today we showed our talent, our team on the pitch. We wanted to win so bad and we showed it."
Al Ahli went into their second leg against Al Rayyan with a two-goal cushion and, despite dominating throughout the first half, it was not until 13 minutes from time that Matthias Jaissle's side added to their lead.
Mahrez showed his balance and poise to control Galeno's lofted ball over the Al Rayyan defence before turning and lifting his shot past goalkeeper Paulo Victor.
The Algerian doubled his side's lead six minutes later with an emphatic finish, stroking home following a lay-off in the penalty area by Gabri Veiga.
The results mean all three Saudi Arabian clubs involved in the competition have qualified for the quarter-finals after Al Nassr booked their place on Monday alongside Qatar's Al-Sadd.
Catch up with all the AFC Champions League action with Flashscore.