The stars for Egypt at Ellis Park were Mohamed Aboutrika, Mohamed Hommos and Essam Al Hadari.
The 30-year-old Aboutrika, who plays for Al-Ahli, is widely regarded as the best player in the world not playing in Europe. The playmaker followed up on his spectacular game against Brazil by causing problems for Italy in the first half.
It was from his corner kick with five minutes to play in the first half that Hommos, also 30, headed home for the game's only goal.
In the second half, the 36-year-old Al Hadari held off an Italian assault, making four brilliants saves. The one time he was beaten he was saved by the bar on Vincenzo Iaquinta's shot with just minutes remaining
"This is a great result," Egypt coach Hassan Shehata told Reuters. "We had a good game against Brazil technically but the result did not go our way. But this gives us great hope for the semifinals."
The only bad news for Egypt was the hamstring injury suffered by striker Mohamed Zidan, who scored twice against Brazil in the 4-3 loss in their opening group game.
Zidan's status for Sunday's game against the USA was uncertain.
The USA needs to beat Egypt by three goals and then get help from Brazil with a win by three or more goals over Italy to move into next week's final four.
June 18 in Johannesburg
Egypt 1 Italy 0. Goal: Hommos 40.
Italy -- Buffon, Zambrotta, Chiellini, Cannavaro, Grosso, Gattuso (Montolivo 57), De Rossi, Pirlo, Quagliarella (Pepe 64), Iaquinta, Rossi (Toni 57)
Egypt -- El Hadari, H.Said, Fathi (Hassan 80), A.Said, Gomaa, Moawad (Farag 69), Aboutrika, Shawky, Abd Rabou, Hommos, Zidan (Eid 56)
Referee: Martin Hansson (Sweden)