Mokhtar ended a successful five-year spell with Petrojet to take charge of Masri, who escaped relegation in the final stages of last season.
His debut was a largely convincing one as the Port Said-based club claimed a deserved win over Farouk Gaafar's Gaish.
Forward Mahmoud Abdul-Hakim, who followed Mokhtar to Masri from Petrojet in the close season, gave the hosts the lead after 30 minutes with a fine free kick.
Gaish striker Salah Amin equalized in the 74th minute but Sameh Adrous, who also moved to Masri in the summer, notched the winner with three minutes remaining.
He connected with a neat cross from diminutive full-back Ahmed Shedid to head home past Gaish keeper Emad Sayed.
ENPPI also benefited from their signings to secure a last-gasp 1-0 win over Gouna.
Playmaker Walid Soliman, who left Petrojet to join ENPPI, produced a fine display and played a key role in helping ENPPI claim all three points.
He had a vicious shot denied by the post deep into stoppage time and striker Ahmed Abdul-Zaher pounced on the rebound to score a vital goal.
Ten-man Ittihad, who fielded two new strikers in Cameroonian Marc Mboua and Hani Al-Egeizi, were held to a 1-1 draw by newly-promoted side MCDR.
The Alexandria-based club lost debutant Felix Awoa after 35 minutes after the Cameroonian defender picked up two yellow cards in quick succession.
Al-Egeizi, however, managed to put Ittihad in front after converting a penalty five minutes later.
MCDR Striker Hossam Osama secured a share of spoils after notching home seven minutes after the interval.