The striker, who joined reigning Nigeria kings, scored a crucial away goal in the Pride of Benue 3-1 defeat courtesy Samuel Onyango's brace plus Jacques Tuyisenge's strike for the Kenyans.
And the former El Kanemi Warriors man has urged all to stay calm as he is upbeat they will overturn the deficit in the return leg of the first round to progress at the Nnamdi Azikwe Stadium in Enugu.
"We actually lost the game 3-0 but fortunately I scored the only goal," Mathias told media.
"I am very happy and give God the glory for me scoring the goal for Lobi. It was my first competitive goal for the club which I really appreciate.
"We've seen the team [Gor Mahia] and seen them play and known their tactics and everything about the way do. I believe and hope with my teammates and the caliber of players we have.
"I believe when they come to Nigeria, we are going to beat them in Enugu. I want to tell my fellow Nigerians that they should calm down.
"It is not over. I believe that we will still get to the Caf Champions League group stage."
A two-goal win without conceding in the second leg in Nigeria will be good enough to see the Nigerian league winners into the draw for the group stages of the competition.