The 19-year-old scored the decisive goal in the Tyne-Tees derby with a venomous 20-yard strike at the Riverside Stadium, sealing three points for the young Magpies in their final Division Two fixture of the league campaign.
Ben Dawson's side now turn their attention to the Division Two play-offs after securing a minimum of fourth place courtesy of Allan's fifth goal of the season in all competitions.
Allan told nufc.co.uk: "It's great to get the win. It's been a long season but to finish off strongly is very good. We wanted to get the win and make sure we have a chance of getting a home draw in the play-offs. Overall, we've done as best as we could.
"It was good to score too. I think I could have had a few more goals this season but it's really nice to get the goal, especially when the game has finished 1-0, which makes it even better.
"To be fair, I just read the pass of the centre-back and then had the ball on the edge of the box. There were few options (to pass) but I thought I'd take it on myself and be a bit greedy for once instead of setting Cal (Roberts) or Elias (Sørensen) up. Luckily enough, it has managed to hit the back of the net."
United's youngsters have picked up 40 points this term - 19 more than last season - and are likely to face an away trip against Reading or Southampton in the semi-final stages in their promotion bid to Premier League 2's top tier.
And Allan believes Newcastle's second-string will head into the play-offs with a strong mentality after ending the week with back-to-back clean sheets, with United achieving a 3-0 victory against Leeds United to reach the Premier League Cup final.
The teenager added: "We'll be going into the play-offs with a lot of confidence. All the credit normally goes to the guys at the top end of the pitch but recently we've defended very well. We have defended really well for the majority of the season and two clean sheets tops that off. There's a lot of credit to go to the defence who don't get as much as they deserve. Without them keeping clean sheets, we wouldn't be able to win many games.
"In the first half, we weren't really at it. The attitude wasn't there and people weren't willing to run. We knew that at half-time and came out trying to rectify that and it changed the game completely. We were in total control and, thankfully, it paid off in the end.
"They (Reading and Southampton) are two good teams who we have both played this season, especially Southampton who we have come up against a few times. There have been mixed results against both sides so we know what we are capable of but we also know what they are capable of too. We'll do as best as we can (in the semi-final). We know what our strengths are so we'll focus on that and try to stop our opponents as much as possible."
