كتب : Hatem Maher
Ahli needed a stoppage-time shot from veteran midfielder Ahmed Hassan to claim a precious victory which cemented their place at the top.
Second-placed Petrojet, who are now six points behind Ahli, missed out on the chance of becoming joint leaders.
"We deserved to get a draw at least. We squandered too many goalscoring opportunities," Mokhtar said after the game.
"I'm not happy with the result, we really deserved something better."
Petrojet relied on playmaker Walid Soliman, who has long been a target for Cairo giants Ahli, to break down the opposition defense but he failed to impress.
He was substituted in the second half, making way for Ghanaian midfielder Cofie Bekoe.
"I had to replace him because he was not performing well," Mokhtar added.
Petrojet, who finished third least season for their best ever position, usually excel in the first half of the season before faltering after the halfway stage.
They appear to be Ahli's only genuine challengers so far this season, with traditional heavyweights Ismaili and Zamalek struggling to be consistent.