Manuwa is just 3-0 in his UFC career thus far and Gustafsson is coming off the fight of his life last year when he took division champion Jon Jones the distance – the Swede arguably deserved to get the decision and title.
Gustafsson certainly did enough to earn an immediate rematch but instead he will face the British KO artist in his own backyard.
The home town underdog may not have many believers against the Swede, but Manuwa has enough confidence in himself to go around.
"My technique has come along by leaps and bounds," Manuwa said in a recent ESPN interview.
"I throw some of the hardest kicks now; those are some of my main weapons. My punches are harder and faster. I'm just a wrecking machine at the moment."
English-Nigerian Manuwa's main attribute is his stopping power, and it's one that he said he first became aware of as a child.
“We used to go to the fairground, and there’s that punchable thing that measures your power,” Manuwa remembered.
“It was from one of those that I knew I could punch. My friends would come around, and we’d have competitions."
So, don't be surprised if Manuwa expects his heavily-favoured opponent at the O2 Arena to end up as just another victim.
After all, what the Brit possesses, he believes he's had since birth. That kind of confidence is hard to shake.
“[My power is] God-given,” Manuwa went on.
"I have 14 stoppages. There are a lot of those moments.”