Striker Kofi Nti Boakye missed a lot of scoring chances but grabbed two to put the Ghanaian champions in good stead for qualification to the next stage.
Kotoko took charge of the match right from the blast of the whistle and sounded the first warning shot on six minutes.
Winger Mpong connected to Abdul Aziz Yusif’s cross but Nguema was saved by their goalkeeper Felide Ovono Ovono.
Kotoko did not relent and kept on asking against a flat-footed Sony Nguema defence manned by Isouf Kananou, Leoncio Mba, Jose Onde and Alfonso Mitigo.
Boakye opened the floodgates on 13 minutes when he headed home an inviting cross from strike partner Yusif.
Midfielder Michael Anaba could have doubled the advantage four minutes later but Ovono in post for Sony Nguema parried away his connection to Mpong’s through pass.
Ovono again denied Boakye in the 20th minute when he spread himself to block a goal-bound shot on a one-on-one contest.
Nguema threatened Kotoko area Angel Nzang attempts a long range which went over the bar but Amoako was alert.
Yusif who had prowled all afternoon got his name on the score sheet with the second on 29 minutes when he tapped home from Akwasi Bobie Ansah.
Anaba atoned for his misses when he finished off a nice move
Boakye directed Helegbe’s powerful shot from inside box to register his personal second and Kotoko’s fourth before the halftime.
After the break, Sony Nguema looked composed but could not keep the rampaging Kotoko attackers.
It took the Porcupine Warriors 70 minutes to get back on the score-sheet through Mpong who raced from the middle and shrugged off a tackle to poke home for the fifth goal.
Substitute Siedu Bancey, who had squandered a lot of scoring chances, managed to score from a nice move.
Defender Joseph Ochaya slotted home the seventh goal on 89 minutes with the Equatoguinean side protesting for an offside.
Kotoko will travel for the return leg next month in Malabo with the winner of the two-legged tie facing either JSM Bejaia of Algeria or Niger’s FC Olympic de Niamey.