Sulemana did not enjoy the best of starts to life as a Saint, but now looks to be firing on all cylinders.
He was the broadcaster's man of the match in Sunday's 3-0 win over Swansea City in the FA Cup third round.
Smallbone told the Daily Echo: "A hundred per cent. I think he's shown here exactly what we want from him and what everyone wants from him.
"I hope and I'm sure this will give him a lot of confidence going forward, especially in front of goal and being positive. He's lightning quick.
"He's got quick feet. He can be a real positive asset for us and have a positive impact in games. Hopefully, for his confidence, this will do a lot of good for him."
The midfielder added: "I think, obviously, the Premier League is the Premier League. It's the best and most difficult league in the world for a reason.
"You're coming up against the best defenders, midfielders and attackers. It's just about finding consistency. I think for him as well, maybe having a run of games.
"Maybe that's what he needs to be able to, you know, get himself up to speed in the Premier League. I think this performance will more than help him."