The powerful frontman has endured a frustrating few months with the Magpies but has worked tirelessly to force his way into the starting line-up.
Francois Zoko's suspension allowed Showunmi to make his fourth start for the club since arriving from Tranmere in the summer, and now he is determined to hold onto his shirt.
He told the club's official website: "It was a few months of pent-up frustration that came out of me when the ball's gone in the net.
"It's just been brilliant to get the start, I've waited a long time for it, and hopefully I've put in the manager's mind that I can obviously perform out there and hopefully he picks me for more games.
"It's been frustrating, because I came here with personal goals but I've kept plugging away and kept my head down in training.
"The manager's seen that I've kept a good level in training over the past few months and I've spoken to him and said that I am ready to play.
"I think I've shown that to him now, but I'm still not match fit so hopefully the more games that I do play, you'll hopefully see a fitter and a better me.
"If I can keep scoring goals, then the gaffer will have no reason to drop me."