Naif Hazazi scored the only goal as Al Ittihad earned a 1-0 first leg advantage over cross-Jeddah rivals Al Ahli in the semi-finals of the AFC Champions League on Monday.
The 23-year-old Saudi Arabia international striker claimed his eighth goal of the tournament so far this season in the 67th minute when he scrambled a right foot shot past Abdullah Al Maiouf to give his side a slender lead ahead of the second leg.
Hazazi's participation had been in doubt before the game due to a knee injury but the forward, who scored twice in the previous round as Al Ittihad saw off Chinese Super League champions Guangzhou Evergrande, was the difference between the sides.
Despite the victory Ittihad's Spanish coach Raul Caneda was less than satisfied with his side's performance at the Prince Abdullah Al Faisal Stadium.
"Towards the end of the game we controlled the proceedings and we should have scored another goal which could have made things easier for us," he said.
"We didn't put in a great performance and we should play better in the next match."
Appearing in a record fifth AFC Champions League semi-final in nine seasons, Al Ittihad always looked the more likely to take an advantage into the second leg in nine days time.
Club captain Mohammad Noor saw his attempt pushed round the post by Al Maiouf in the 19th minute and, from the resultant corner, Osama Al Harbi's header was cleared off the line by Kamel Al Mor.
Victor Simoes forced a fine save out of Mabrouk Zayed at the other end as the half wore towards its close before Al Maiouf was called into action again to deny Noor.
Al Ittihad were in the ascendancy and it was only a matter of time before the two-time Asian champions claimed the lead they deserved when Hazazi slotted home from six yards out, with the goal standing despite the ball bouncing up and hitting the forward on the arm in the build-up to the goal.
Both clubs play their home matches at the 23,000-capacity Prince Abdullah Al Faisal Stadium with Al Ittihad designated as the home team for the first leg.
The two teams will meet again on October 31, with the winners meeting either Uzbekistan's Bunyodkor or Ulsan Hyundai from South Korea in the final on November 10.