Striker Kwame Boateng fired the Porcupine Warriors ahead with a sublime finish on the 72nd minute mark. Ghana U20 striker Dauda Mohammed supplied a great pass to Boateng and he mesmerized two Hasmal defenders before firing home a low drive.
Hasaacas could have conceded more goals but former Ghana goalkeeper George Owu produced great saves with feline agility to keep the visitors in the game until Boateng broke the deadlock for the hosts.
Hasaacas trainer Yussif Basigi named the experienced George Owu in goal. The 2006 FIFA World Cup Black Stars custodian returned to the Baba Yara Stadium to face his former employers who are enduring a tough start to the season.
Defender Amos Korankye was dropped to the bench but Eric Bekoe and Samuel Afful formed a potent strikeforce for Hasmal.
The under-pressure David Duncan handed a debut starts to defender Emmanuel Asante who was among the injured crop of players at the club. Ernest Sowah held down his place in defence while Kwame Boateng and Dauda Mohammed led the attack.
Kotoko stepped into gear from the blast of Maxwell Hanson's whistle and created a host of chances. But George Owu produced quality saves to deny Ahmed Adams and Dauda Mohammed.
While Kotoko perpetuated their dominance in midfield and continued expressing superior physique over Hasaacas, torrential rains started pouring out cats and dogs.
Kwame Boateng was held at bay by the Hasmal defence who defended with heart and soul placing bodies as shields to block ferocious drives.
In one moment, Ahmed Nyame tried a powerful drive from the edge of the box but Thomas Aboagye dived to used his body to divert the ball to corner, injuring Owu in the process.
Hasaacas's one goal attempt in the first-half summed up their evening. Ernest Sowah was not tested by Hasaacas in the entire 45 minutes. But Kotoko created eight chances but failed to break the visitors' defensive network.
Basigi remained on the touchline to issue instructions to his charges despite the pelting rains down.
Obed Owusu was returned to attacking duties as he replaced Michael Yeboah six minutes into the second-half.
While Hasaacas guarded their area jealously Kotoko piled more pressure, asking all the questions. And, Kwame Boateng had the answer in the 72nd minute.
The striker signed from relegated Great Olympics sublimely danced his way around two Hasmal defenders and arrowed a clinical low drive to George Owu's net. Dauda Mohammed supplied an articulate pass from the vital area and found Boateng. The promising striker traversed the area, mesmerized Kingsley Adjei and Arhinful with quick-feet and fired a low drive to beat Owu for the opening goal.
Kotoko XI: Ernest Sowah - Amos Frimpong, Samuel Kyere, Richard Osei Agyemang, Ahmed Adams - Theophilus Nyame, Michael Yeboah, Stephen Nyarko - Kwame Boateng, Dauda Mohammed, Emmanuel Asante.
Hasaacas XI: George Owu - Daniel Agyin, Thomas Aboagye, Augustine Arhinful, Kingsley Amfo Adjei - Albert Osei, Fatawu Mohammed, Saliw Babawo - Eric Bekoe, Samuel Afful, Emmanuel Ankobeah