The Kenyan champions will be seeking to overturn a 4-1 defeat suffered in the first leg during the return leg set for September 29 at Kasarani Stadium.
Muguna believes the tie is not lost and has vowed to fight for the club as they strive to get a good result in Nairobi.
“Win or lose I will never hide, life is tough and so is football since everybody wants to be associated with success,” Muguna wrote on his Facebook page.
“We are here to defend and fight for this club n we will do it as a team until the end…onto the next one and see you guys on Thursday.”
Meanwhile, Gor Mahia coach Steven Polack has also assured fans they will fight to get the win which will guarantee them passage to the group stage.
“We have put the defeat behind us. Gor Mahia will no longer play defensive football but we will be attacking because we need to score goals," he said.
“We have nothing to lose since we still harbour hopes of eliminating USM Alger. It is not the time for blame games but fixing one or two areas.
“I will discuss with the goalkeeper coaches on who should be fielded but I can’t blame David [Mapigano] entirely for the defeat.”
The Briton, who guided Gor Mahia past the preliminary round after crashing Burundi's Aigle Noir 5-1 in Nairobi, says inexperience cost them in Bilda, where they found themselves trailing by three goals at half-time.
"We lost to [USM Alger] not because we were a poor team but due to little mistakes and a loss of concentration,” Polack continued.
“We had 16 players but only one or two have the experience of playing in continental and competitive matches. I don’t want to blame any player or management but I take responsibility for the defeat.”
Gor Mahia will need to win by a 3-0 margin to proceed to the group stage which comes with a reward of Sh55 million.