The hosts took the lead in the third minute through Mahmood Qassim but Al Hilal hit back in the 21st minute through Tareq El Taib.
Mirel Radoi scored from the spot early in the second-half before Yasser Al Qahtani wrapped up the win for the Saudi Arabians with a fine strike in the 64th minute.
The victory means Al Hilal are in second place with eight points, six ahead of Saba Battery with two games left to play.
The hosts made the ideal start when a mistake in the third minute by goalkeeper Mohammad Al Deayea allowed Qassim to send a speculative effort from distance over the goalkeeper and into the net.
Al Ahli came close to adding a second just four minutes later when Waleed Ahmad’s header bounced just wide of the goal while the visitors had the ball in the back of the net with their first real foray into Al Ahli’s half but Yousef Jabir’s effort was ruled out for an earlier infringement.
Milad Midavoodi then used his trickery to dumbfound a defender and work space for himself before unleashing a testing drive that warmed the hands of Al Deayea.
But Al Hilal were level in the 21st minute when goalkeeper Obaid Al Taweela could only get a hand to Christian Wilhelmsson’s low effort and El Taib swept the ball into the roof of the net from a tight angle.
The visitors twice had chances to take the lead just before the break as first Seol Ki-hyeon shot just wide while Wilhemmson’s low drive went just the wrong side of the right-hand post.
And their pressure finally paid off when they went further ahead in the 53rd minute after they were awarded a penalty and Radoi stepped up to fire a powerful spot kick off the underside off the diving goalkeeper and into the back of the net.
The visitors then went further ahead just after the hour mark when Seol brilliantly picked out Al Qahtani on the left side of the area and the forward curled a fine effort into the far corner of the net.
The game belonged to Al Hilal in the closing stages and they had the chance to add another just before time but the influential Seol shot wide when well placed before tempers flared in the closing stages when the Saudis were left with 10 men on the pitch after Al Qahtani was red carded for a clumsy late tackle in stoppage time.