Seven-time champions Ahly went in front after 14 minutes through a free-kick delivered by their durable campaigner Mohamed Aboutrika.
Thabo Matlaba fired home the vital equaliser for Pirates in full-time stoppage time to leave the second leg final wide open.
"We have something to play for," Pirates coach Roger de Sa said. "A 1-1 draw at home not the greatest result, but I believe we can score there in Egypt.
"We will attack in the second leg and hope for the best."
Ahly coach Mohamed Youssef said, "A 1-1 draw away from home is a fair result. There is still another 90 minutes to be played in Cairo.
"We hope to change our approach at home and we will win."
Abdul Zaher was on target for Ahly after 51 minutes, when he was set up by Aboutrika, but it was disallowed for offside.
Home team Pirates, seeking a second CAF Champions League trophy 18 years after their first, dominated possession and were full of running and spirit.
But Ahly showed class and experience to frustrate their hosts.
Pirates, who beat the Egyptian giants 3-0 in a group game, had few chances at Ahly's goal in this absorbing contest.
First, Lennox Bacela was denied by Wael Gomaa in the 57th minute when the striker dashed into the 18-yard box and his final shot was blocked for a corner by the 38-year-old Ahly skipper.
Moments later, Ahly goalkeeper Sherif Ekramy was forced to make a big save after Andile Jali let fly from a good distance.
Pirates, cheered on by a packed Orlando Stadium, took the game to their opponents from the first blast of the whistle.
The home team were restricted to shooting from distance with the likes of Rooi Mahamutsa, Oupa Manyisa and Matlaba all trying their luck from long range.
'The Buccaneers' were camped inside the Ahly half, enjoying more of the ball, but just could not find their way to the goal of the defending champions.
In a rare Ahly attack, Pirates goalkeeper Senzo Meyiwa parried a fierce shot by Zaher for a corner in first half stoppage time.
With Ahly on target to take the first leg honours Pirates grabbed a share of the spoils when Matlaba struck in injury time of an absorbing contest.
The return leg final will be played in Cairo next Sunday.
The overall winners of this final will pocket a prize money of $1.5m and represent Africa at the 2013 FIFA Club World Cup in Morocco in December.