The Red Devils, who are chasing a fifth successive league title, failed to avenge their 1-0 defeat to Talaat Youssef's side in the league's first half.
They had mercurial midfielder Mohamed Barakat sent off in the second half for picking up two yellow cards, one for diving and another for a clumsy tackle on a Police defender.
Ahli are still in charge of the table on 42 points, four ahead of second-placed Ismaili, who have a chance to narrow the gap to just one point if they beat Petrojet on Monday.
Police moved to ninth place on 27 points, seven clear of the relegation zone.
The hosts struggled to break down Police's tight defense during the first half as they sorely missed the presence of injured playmaker Mohamed Abou-Treika.
Veteran midfielder Ahmed Hassan and Barakat supported lone striker Flavio but they were unable to assist the Angolan.
The visitors, who relied on counter attacks, almost stunned the home crowd after nine minutes.
Abdullah Farouk's shot from the edge of the area deflected off a defender and looped towards goal.
Palestinian keeper Ramzi Saleh, who made his third successive start instead of the error-prone Amir Abdul-Hamid, superbly tipped it onto the bar to prevent Ahli from conceding an early goal.
Ahli then dominated possession and had two identical opportunities through Hassan.
The former Anderlecht man was twice found unmarked inside the area but his left-footed shots were blocked by Police keeper Mohamed Khalaf.
Barakat Off
Ahli coach Manuel Jose made two substitutions during the second period in a bid to improve his side's attack.
Strikers Hani Al-Egeizi and Ahmed Belal were introduced to play alongside Flavio.
But Jose's plans suffered a blow after Barakat received his marching orders six minutes past the hour mark for lunging at an opponent.
The Portuguese tactician was forced to substitute Angolan hitman Flavio with right-back Ahmed Sedik.
Ahli kept pushing forward despite their numerical disadvantage but failed to clear any clear-cut chances. Police held firm to secure a share of spoils with the defending champions.