By Inas Mazhar
BBC Sport, Cairo
Hossam Hassan (left) won the 2002 Champions League with Zamalek
One of Africa's most intense rivalries will go up a notch on Sunday when Egyptian sides Zamalek and Ahly meet in the Champions League semi-final.
Such is the history between the sides that not even the only Egyptian to have played for both clubs is prepared to make a prediction.
This is despite the fact that Ahly are currently unbeaten in 44 matches, having last suffered defeat when losing a domestic cup tie against Arab Contractors in June 2004.
"The Ahly-Zamalek derby is always very special for both teams," former Egyptian national team captain Hossam Hassan told BBC Sport.
"Both teams will be looking for victory, so they will both be playing for it."
"Whatever preparations they have undergone or whatever difficult situations any of them are going through, once you are in the pitch it is something different.
"The result is always unpredictable and it's not always the best team that wins."
Hassan, Africa's most capped international, spent nearly 22 years of his career with Ahly and another three with Zamalek.
The latter lost 5-0 in the league on Tuesday, a result which threw the club's Champions League preparations for the first leg into turmoil.
Hassan, who now plays for Masry in Port Said, said he would be one of many thousands of Egyptians watching the match but refused to say which team he wanted to win.
However, the 40-year-old did reveal that he would like to end his career at either of the two Cairo giants.
"I have played for Ahly and for Zamalek and I enjoyed playing for both, but I can't choose where I end my career," he explained.
"It's difficult. At one of the clubs, the fans want me but the management doesn't while at the other, the management wants me but the fans don't."
Hassan will have the thoughts of both sets of fans in mind this weekend, saying that he feels sorry for those who will not be able to watch the match live.
Sunday's tie will be held at the Military Academy, which hosts around 40,000 spectators, since the Cairo Stadium is undergoing refurbishments.
The second leg of the tie will be played on 16 October, while the two-legged Champions League final will conclude in November.