Egypt's goalkeeper Essam El Hadary set the record for being the oldest player to start in a World Cup game and had an eventful debut.
Mohamed Salah put Egypt ahead in the 22nd minute with when he deftly controlled a long ball from Abdalla Said that split the Saudi defence and then nonchalantly lobbed the ball over goalkeeper Yasser Almosailem. That was Egypt's first goal in open play at the World Cup since 1934.
Salman Alfaraj got the Saudis level with a penalty kick in first-half stoppage time after Ali Gabr was adjudged to have brought down Fahad Almuwallad in the area. The decision was confirmed belatedly after a video review.
Almuwallad had earlier missed a chance to equalize when El Hadary brilliantly saved a penalty. The 45-year-old El Hadary anticipated well, dived fully to his right, flicked his left hand up to push the spot kick onto the bar, before the ball was cleared.
He was unable to repeat when Alfaraj lined up against him, going the wrong way and having no chance of stopping the shot.
The second half was a tamer affair until Salem beat El Hadary from an acute angle.