Jorge Jesus' side beat the previous record of 27 consecutive victories by Welsh Premier League champions The New Saints (TNS) from the 2016-17 season. TNS had beaten Ajax Amsterdam's 26-game winning streak, a record that had stood for 44 years.
"This is truly an incredible achievement and I want to thank everyone at the club for their part in this momentous winning record," said manager Jesus of his side whose world record streak started on September 25.
"As I have said throughout this period, however, records do not matter as much as trophies. It is up to everyone at Al-Hilal to ensure that we close out the season as Roshn Saudi League champions and meet our targets in the cup competitions. Only then can we truly celebrate."
Yasser Al-Shahrani struck in the 61st minute and Malcom added a second goal deep into added time at King Abdullah Sports City after Al-Hilal's goalkeeper Mohammed Al-Owais had frustrated an Al-Ittihad side seeking to overturn a 2-0 first leg deficit.
A no-nonsene finish to end the tie 🙅�♂�— #ACL (@TheAFCCL) Malcom is on the way to his first #ACL Semi-Final with Al Hilal!#ITHvHIL pic.twitter.com/VLQzAMwKrIMarch 12, 2024
Jesus' side lead the Saudi league with 65 points, 12 ahead of Cristiano Ronaldo's Al-Nassr, who were eliminated from the ACL 24 hours earlier after a penalty-shootout loss to Al-Ain.
Al-Hilal, the winners of the title a record four times and 2022 runners-up, will face Al-Ain in the semi-finals.
They are unbeaten this season and have reached the semis of the King's Cup as well as the Champions League.Â
Jesus's side can extend their winning run when they host Damac, the last side to beat them, in the Saudi league on Saturday.
In the eastern half of the ACL draw, Ulsan Hyundai booked their berth in next month's semi-finals by beating Jeonbuk Motors 1-0 thanks to Seol Young-woo's first-half volley to claim a 2-1 aggregate win over their fellow South Koreans.
Hong Myung-bo's side will face either Japan's Yokohama F Marinos or Shandong Taishan from China in the next round, with the pair due to meet in the second leg of their quarter-final on Wednesday night.
Harry Kewell's Marinos team will take a 2-1 lead into the game at Yokohama International Stadium.