The 35-year-old striker showcased his skills in the 37th minute, controlling the ball inside the area and delivering a powerful low strike to give Ahly the lead.
However, Gouna's Algerian forward Ahmed Belhadj equalized just before halftime with a penalty kick, after the ball was blocked by Mohamed Hany's hand inside the area.
With this result, Ahly claimed the top spot in the league with 13 points, edging out Pyramids FC on goal difference.
Gouna, on the other hand, moved up to 8th place with nine points following the draw.
The game kicked off with intense pressure from Gouna, as they had a goal disallowed in the first minute.
Ahly's goalkeeper Mohamed El-Shennawy attempted to clear the area, but Ayman Saad blocked it with his elbow and sent the ball into the net. However, the Video Assistant Referee (VAR) ruled it out.
Belhadj had a clear scoring opportunity in the 12th minute, but El-Shennawy made a crucial block.
He then attempted a sharp strike from outside the area in the 25th minute, only to be denied by El-Shennawy once again, resulting in a 1-1 draw at halftime.
Modeste finally lived up to the fans' expectations by scoring his first goal in eight appearances since joining the team last summer.
Ahly's coach, Marcel Koller, introduced more substitutes from the bench in a bid to regain the lead.
Karim Nedved was replaced by Emam Ashour, Mohamed 'Afsha' Magdi made way for Aliou Dieng, and Taher Mohamed Taher was substituted by Percy Tau.
In the 75th minute, substitute Karim Fouad came close to giving Ahly a second lead with a powerful strike from a free-kick, but it hit the crossbar, denying them the advantage.
Modeste had another opportunity to score during injury time, launching a rocket from inside the area, but Gouna's defense managed to block it, resulting in a 1-1 draw between the two teams at the final whistle.
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