"Nigeria's game is the toughest," Youssef told FilGoal.com in a phone call from Congo.

"They are the strongest team in the group and the result would be decisive," the former Zamalek star added.

Egypt edged 1-0 past Cameroon in the opener to split Group B summit with Nigeria, who crushed Zambia 4-2.

Youssef was satisfied with the victory over Cameroon and said that the poor pitch made the mission harder for the young Pharaohs.

The artificial turf of the match venue turned into small swamps, hindering attempts of dribbling or passing.