After drawing with Belgium in their opening match, Egypt knew victory would put them in a strong position to reach the Round of 32. However, they were forced to recover after a difficult first half against an energetic New Zealand side.
The All Whites started brightly and deservedly took the lead when defender Finn Surman powered home a header from Tim Payne's corner. New Zealand continued to threaten, with Elijah Just and Sarpreet Singh causing problems, while Egypt struggled to find their rhythm before the break.
Omar Marmoush and Salah both came close as Egypt searched for an equaliser, but New Zealand held their advantage going into half-time.
The Pharaohs emerged with far greater intensity after the restart. Goalkeeper Oufa Shobeir kept his side in the contest with an important save from Callum McCowatt before Egypt finally found their breakthrough.
Mohamed Hany delivered an inviting cross that was headed home by Mostafa Ziko just before the hour mark. The goal transformed Egypt, who suddenly looked full of confidence and attacking intent.
Salah then produced the decisive moment. The captain exchanged passes with Ziko inside the penalty area before calmly finishing into the far corner to complete the turnaround and send the Egyptian supporters into celebration.
With New Zealand struggling to respond, Egypt sealed the victory eight minutes from time. Salah's corner was met by substitute Mahmoud Trezeguet, who guided a header into the net to cap a superb second-half performance.
"It's a great achievement for all the players. It's a great win. It's a great vibe. The next game is very important," said Salah after the match.
Egypt coach Hossam Hassan praised both his players and the travelling supporters.
"The stadium felt as if we were in Egypt. The fans made it feel as though we were playing in Egypt," Hassan said.
New Zealand captain Chris Wood acknowledged Salah's influence but highlighted Egypt's overall quality.
"You can't just focus on one player. He can pop up with a goal at any time, and he showed that," Wood said.
The result lifted Egypt to four points from two matches and put them in pole position to reach the knockout stage. The Pharaohs now face Iran in their final group game, while New Zealand must defeat Belgium to keep their hopes of progression alive.