Hugo Bross' men were torn apart by the rampant Super Eagles thanks to goals from Odion Ighalo, John Obi Mikel, Victor Moses and Kelechi Iheanacho at the Godswill Akpabio Stadium.
And the ex-international, who extolled the impact of Mikel and Ighalo's return, believes the victory over the reigning African champions have brought back their winning mentality.
"It was a fantastic game. Mikel killed them with his long passes as he always wants to put the ball behind the defenders and Ighalo was impressive too," Garba told Goal .
"I think the Cameroonians lost their heads along the way which was good for us and we got the first goal before Mikel scored the second, Moses the third and Iheanacho the fourth.
"I must say it was a fantastic performance. This is the kind of situation we looking to score the goals first.
"In the first five minutes, I was thinking the game was going to be very tough for us and after we got the first goal, believe everything changes.
"Whenever we got the ball, we have the bulldozer up front with Ighalo and Mikel doing very well to get behind the Cameroonians defence. Simon and Victor on the wings including the holding midfielders - Ndidi and Onazi were all fantastic today [Friday].
"The three points were very important. No, matter how we play and beating Cameroon 4-0 was not easy. If you think you're, the away team can come and shock you.
"Football is changing, I saw Ghana struggling at home against DR Congo. I think the Super Eagles were good today scoring four good goals."