In a statement, ZGGG President Murtala Abdullahi praised Matawalle's influence and loyalty to the APC, despite leaving office as governor two years ago.
Abdullahi noted that the electoral process was marred by attempts to sway the contest, but commended APC supporters for defending their mandate.
The group urged the Independent National Electoral Commission (INEC) to guarantee a transparent supplementary poll, ensuring the will of the people is reflected.
ZGGG applauded Matawalle's grassroots presence, crediting him with keeping the APC united, and urged APC stakeholders to consolidate their momentum, stressing internal unity would strengthen the party in future elections.
The group also called on security agencies to ensure adequate protection for voters during the supplementary poll.