The young Magpies, currently occupying fourth place in the table on 26 points, host their West London counterparts at Whitley Park (kick-off 7pm GMT).
After registering four league wins out of their previous five matches, Stephenson - who signed his first professional contract with his boyhood club last summer - is determined to continue a similar run but expects a difficult test against the Cottagers' second-string, who have won 16 of their 19 league fixtures this term.
The 19-year-old, who has netted 13 goals in all competitions at under-23 level this season, told nufc.co.uk: "It's an important game for us as we need to get points to stay in the play-off spots. Any game is winnable. We've been on a pretty good run in the league and the lads are looking forward to it.
"We have a couple of games in hand over the teams around us and those games are the ones we must be winning to get as much points as possible.
"We are about seventh or eighth in the league before we won four of our last five games. That has given the team a good winning mentality and we are more than capable of continuing to win.
"Every game for us is massive. There is only a few points which separates the majority of the league. It's been a good season so far and very tense but that's what you want.
"Most players will enjoy the most tense games because there is more pressure riding on them and it makes you perform better to get good results. It's a great learning experience."
Despite the reverse fixture ending in a 3-1 defeat for the young Magpies back in September, Stephenson believes United's youngsters can learn from their previous experience against the Whites.
The Blyth-born forward, who scored inside two minutes of the clash in the capital, is also keen for Newcastle to build on their positive form of late, with six victories in their last eight competitive matches.
Stephenson, who received a Premier League 2 Player of the Month nomination in August, added: "We started really quickly in the first-half, scoring early on. We played really well and then we dropped off in the second-half, not playing as well.
"Some of the goals were errors from ourselves but if we can cut them out, we will be able to get a good result.
"In training, we've recently been splitting off into two groups - defenders and strikers. That has been helping and we are able to score a lot of goals and keep clean sheets too.
"Everyone is confident, we have been performing well both individually and as a team and we're all motivated to keep going until the end of the season."
Admission on Monday night is free for season ticket holders and Members, otherwise it's £3 for adults and £1 concessions.
