Newcastle's second-string, who travel to Lincolnshire for their third Premier League Cup group fixture on Friday night (kick-off 7pm GMT), currently sit in second spot of Group C but could move a step closer to qualification for the knockout stages with a win against the Iron the Sands Venue Stadium.
After an impressive 4-2 win in Premier League 2 against Stoke at Whitley Park, in which Longelo scored and assisted after coming on as a second half substitute, the 20-year-old forward is looking for his side to continue where they left off on Monday night.
"It's a very important game," Longelo told nufc.co.uk. "Everyone wants to do well in a cup competition and try to win some silverware. We're heading into that game with a winning mentality which is good for us as a team.
"Hopefully, we can go one step further than we did last year and showcase our talent and show people how good a side we are.
"I think we deserved that win (against Stoke) on Monday as we've been working hard every single day in training and it's just about time that the good results are started to kick in.
"Coming from behind twice shows that the squad have a strong mentality in the changing rooms and we all believe in ourselves. We believe we could be doing much better and I think it's finally starting to show."
After a 1-1 draw against Benfica B in the Premier League international Cup, Longelo - who joined Newcastle from West Ham United in 2018 - believes his side are beginning to look forward after a difficult start to their campaign.
The winger also provided an assist for United's only goal against the Portuguese outfit and has been pleased with his recent performances after a recent comeback from a hamstring injury sustained in September.
Longelo added: "The team are starting to click. After the Benfica game, I think we should have got all three points but we were just unlucky. We just have to focus on the next game and the next task that comes along.
"Everyone knows that we need to tighten up on our defence and that's not just the defenders and goalkeepers. It starts from the front line so, as a team, we all need to tighten up. If we can concede less goals together, I think we will be fine.
"I'm pleased with my own game at the moment. I know you can't start every single game but other players need to have a chance to prove themselves as well.
"When you do come on, you just have to show yourself and prove to yourself why you shouldn't be on the bench and do everything you can to make the manager continue picking you."
