Ittihad won the first leg match 3-1 at Prince Abdllah Al-Faisal Stadium two weeks ago in Jeddah. Mauricio Molina scored the only goal of the match in the 85th minute.
Prince Nawaf bin Faisal, president of the General Presidency Of Youth Welfare, phoned and congratulated Ittihad club president Muhammad bin Dakhel for the achievement. Prince Nawaf said that he was proud of Ittihad's achievement and that the club will receive a SR1 million reward. Bin Dakhel also received a congratulatory phone call from Ahli Club President Prince Fahd bin Khaled.
In the other quarterfinal, Lee Dong-Gook scored four as South Korea's Jeonbuk Motors dismantled Japanese rivals Cerezo Osaka 6-1.
Trailing 4-3 from the first leg, Jeonbuk dominated throughout as they dispelled last week's crushing away loss to Cerezo with a scintillating second-half performance in Jeonju.
Before the game the Koreans' coach Choi Kang-Hee had urged his players to banish the memory of defeat in Osaka - a game, which they led three times - and his team responded with a barrage of goals to take a 9-5 aggregate victory.
Jeonbuk had to wait until the half hour mark to break the deadlock with a goal from Brazilian star Eninho, who latched on to a sweetly timed Luiz Henrique pass and drilled a shot beyond the Cerezo goalkeeper Kim Jin-Hyeon.
The goal sparked Lee into action. The South Korean international and former Middlesbrough striker opened his account early in the second-half heading home from a corner.
He doubled his tally on 55 minutes with a 25-yard effort squirming under Kim, and completed his hat trick less than 10 minutes later with a powerful volley from the edge of the box, which deflected beyond the unfortunate goalkeeper.
His fourth came in stoppage time, after attacking midfielder Kim Dong-Chan had added a fifth for the rampant home side, capping a good day's work for the prolific veteran striker.
Cerezo, who lie mid-table in the J-League, scored a consolation goal with around 20 minutes to go after Rui Komatsu neatly finished a defense-splitting Fabio Lopes pass.
Suwon Bluewings, who complete the Korean quarterfinal contingent, face a tricky away date in Iran on Wednesday against last year's runners' up Zobahan after playing out a 1-1 draw in Korea.
In Wednesday's other tie, Iran's Sepahan have it all to do after they were stripped of a their win against Qatari outfit Al Sadd and handed a 3-0 forfeit for fielding an ineligible player in their quarter-final first-leg.
The Asian Football Confederation (AFC) erased Sepahan's 1-0 first-leg victory and replaced it with a 3-0 defeat late on Monday. The teams will play the second leg in Doha.
