The visitors took a surprise lead as Ahmed Khalil opened the scoring on 12 minutes.
But Al Hilal levelled the score in the 32nd minute through former AFC Player of the Year Yasser Al Qahtani and Mirel Radoi scored from the spot in the first minute of stoppage time to give Al Hilal their first win in the competition.
It was Al Hilal’s second win in four days after Leekins led his new charges to a 2-0 win over Ettifaq to keep them in the hunt for the Saudi League title.
"I am very glad with this victory which is the first for us in the competition," said Leekins.
"The most important thing is that we secured the three points."
Leekins now switches his attention back to the Saudi League as they prepare for a crucial clash with Al Ittihad on Sunday.
"I will ask my players to forget this game and the win that we achieved as we need to concentrate on our next game in the Saudi League against Al Ittihad, which means a lot for me and my players too," he added.
"Some of my players were not fully recovered from their injury and they were in need for rest but I started with them to prepare for Al Ittihad next Sunday.
"I think the match was very difficult especially in the second half and Al Ahli were a strong competitor.
"After the end of the Saudi football season, I will work to build the team and prepare the players for the next matches in the AFC Champions League and I am sure we have enough time to achieve our goals.
"I am looking forward to leading Al Hilal to top spot in the group because I have a good squad.
Al Ahli coach Ivan Hasek believes his side deserved a point from the game.
"I think that both teams were equal in everything and the fair result of this match would have been a draw," he said.
"In football, if you want to win you need to score from the chances and Al Hilal worked until the last minute of the match and they won the game.
"I am very satisfied with my team’s performance and the players played a very good match.
"We have three remaining matches and I think our chances of reaching the second stage are open and we will try to secure all points."