The teenage midfielder, brother of Sean, has played a consistent part in the under-23s side this term, with the young Magpies sat in the Division Two play-off spots, occupying fifth place after seven wins from their previous nine league outings.
Following an impressive 3-0 victory over Southampton in the Premier League Cup last week, the young Magpies side turn their attention back to league action, facing the Royals at Wycombe Wanderers' Adams Park (kick-off 7pm GMT).
Longstaff reflected positively on the recent cup win against the Premier League 2 leaders - and assessed the effect that their recent run in form is giving the squad.
"After the win over Southampton, the mood is very good," Longstaff told nufc.co.uk. "We want to show people we are a good team as we've worked very hard to get to this stage. We played really well and I spoke with some players in the group, saying it was one of the best games we've played for a while as a team, keeping a clean sheet which will always give you a good chance of winning games.
"After a victory, it always feels like the camp is a lot better. The lads are laughing and joking, while looking forward to the next game because when you are on a good run, you always want to keep playing and pick up wins to move up the table.
"The mood stays high in the camp and it keeps the momentum going. Everyone is enjoying training and working hard to compete for places in the team."
Newcastle squandered a two-goal lead in the reverse fixture against Reading, suffering a 4-2 defeat at Whitley Park in September, but Longstaff remains upbeat ahead of Friday's fixture, knowing his side are capable of a stronger performance.
Longstaff added: "To be fair, I didn't think we were great in that game and I know a lot of us will be wanting to go down there and win.
"Reading are two places above us in the league table so if we want to reach our achievements that we have set as a team, we need to be going there and trying to get a result.
"We have a strong self-belief and know that we can pick up results away from home. We'll stick to our game plan and know what we need to do but I think we must try to take advantage of having an extra game in hand to make sure we can stay near the top of the table and have a fighting chance to get into the play-off spots or get promoted."
The young Magpies have scored 37 league goals this season - the highest in the division - with top goalscorer Elias Sørensen and Cal Roberts netting a combined total of 21 goals.
Both players have earned loan moves in January but, despite their absence, Longstaff has been impressed with squad members who have stepped in to take their opportunity.
"At the start of the year, we had Elias scoring a lot of goals and Cal assisting many and scoring. They've both gone out on loan and it has been a question of whether other people could step up and I think we've had that with players as Yannick Touré, who is on fire at the minute.
"Kelland (Watts) scored a hat-trick last week so lots of people are chipping in from everywhere which I think is what we are going to need as a team if we are going to be successful.
"In football, as the season goes on, players can pick up injuries or go out on loan in the under-23s but having players who can come into the side and show their class to make a strong impact is helping us massively in winning matches."
