Two goals deep into extra time helped Hilal avert a shock exit and advance 5-4 on aggregate despite losing to Qatar's Al Gharafa 4-2 in the second leg in Doha.
Gharafa stormed to a 3-0 lead in the first half with goals from Mirghani Al Zain, Younus Mahmood and Othman El Assas to level the tie on aggregate and send the match into extra time. Mahmood scored 11 minutes into extra time to put his team on the brink of a stunning upset but Al Hilal's Yasser Al Qahtani and Eysa Al Mahyani scored in the final two minutes to snatch away the victory.
Shabab also clinched a place in the semifinals even though it lost 1-0 to Jeonbuk Hyundai Motors of South Korea at King Fahd International Stadium.
Kim Jee-wong's long-range strike midway through the first-half cut the 2-0 aggregate deficit, but despite several good chances in the second half, the visitors were unable to come up with another goal to send the match into extra time.
Shabab had the most opportunities in the second half, including a dangerous free kick from Marcelo Camacho which was pushed around the post by Kim Min-sik in the 50th minute. Nasir Al Shamrani Al Shamrani fired over from the edge of the box six minutes later.
Lee Dong-gook then wasted Jeonbuk's best chance of the second half as the striker fired wide from eight yards.
In South Korea, Seongnam went through 4-3 on aggregate after losing 2-0 to Suwon Bluewings in an all-South Korean quarterfinal.
South Korea international Yeom Ki-hoon and Lee Sang-ho scored for two-time champion Suwon at Suwon World Cup Stadium.
Yeom curled a 25-meter free kick over the wall and into the top corner in the 32nd minute. The deficit was reduced to one goal after Brazilian midfielder Marcelo's short pass to Lee inside the area allowed the striker to shoot into the bottom corner in the 59th.
Zob Ahan needed an 80th-minute goal from Mohammad Reza Khalatbari to seal its place in the final four.
Khalatbari punished Pohang for its wastefulness, taking a pass from Ghasem Hadadifar to fire past goalkeeper Shin Hwa-yong.
Pohang had led in the 10th minute with a well-worked goal.
Brazilian striker Mota freed Jung Hong-yoon on the left side and his low cross was swept into the net by international midfielder Kim Jae-sung.
