The Saudi giants are seven points clear at the top of the standings with 59 points from 21 matches, ahead of Cristiano Ronaldo's Al Nassr, who beat Al Shabab 3-2 on Sunday.
Coach Jorge Jesus' team have achieved 14 consecutive victories in the league, ending Al Nassr's previous record of winning 13 matches from November 2013 until February 2014.
Sergej Milinkovic-Savic gave Al Hilal the lead in the 40th minute with a header after a corner. Salem Al Dawsari added the second goal from close range in first half added time.
Al Hilal's evening would have been perfect, but top scorer Alexander Mitrovic received a yellow card and will miss the next match, against defending champions Al Ittihad, due to cards accumulated.