The Academy booked their place in the Barclays Under-18 Premier League Play-Offs after a 1-1 draw against Arsenal on Friday afternoon.
Former Arsenal youth striker Jordan Brown earned the Hammers a sixth minute penalty after being fouled by Stefan O'Connor, which was converted by captain Kieran Bywater.
The hosts were denied the full three points in the second half however when Ainsley Maitland-Niles pounced onto a slip in the Hammers defence to finish into the top corner.
The Hammers needed a single point going into this fixture to ensure that London rivals Fulham could not catch them and U18 boss Steve Potts had an extended group of players to choose from.
Reece Burke returned to the centre of defence to partner Manny Onariase, whilst Josh Cullen shrugged off a recent injury to take a place on the bench. Ben Marlow's injury problems meant he had to sit out of another fixture, whilst U16s defender Josh Pask took up a holding role in the middle of the midfield.
With the pressure on the Hammers to get a result, the hosts couldn't have asked for a better start when Brown burst into the penalty box, only to be dragged to the ground by O'Connor. It was down to Hammers captain Kieran Bywater to step up and bury his 18th goal of the season.
The Hammers continued to dominate and should have been awarded another penalty straight away when Brown again got goal side of O'Connor, forcing the towering defender to apply heavy pressure on the Hammers forward, although the referee did not agree.
Into the second half and the Hammers kept their foot on the accelerator as they searched for a second goal, which they almost got when Brown again found a route into the penalty box, although he slipped when trying to find a team mate in the middle to finish.
It was a fiery game that both sides desperately wanted to win, which led to a heated moment between captain Bywater and Arsenal skipper Glenn Kamara when the former reacted badly to a needless challenge off the pitch, although both players shook hands after receiving yellow cards.
West Ham had a golden opportunity to wrap the game up in the 71st minute when substitute Jaanai Gordon used his pace and power to run through on goal, but Gunners keeper Josh Vickers pulled off a brilliant save.
Just a minute later and the visitors were level when a crossfield ball towards Maitland-Niles caught the Hammers unaware and he held his nerve to smash the ball into the top left hand corner of the net.
The goal gave Arsenal confidence as the Hammers started to tire, but the hosts continued to push for a winner and almost got it when Gordon again found a way through the Arsenal defence, although his shot only made it into the side netting.
Speaking after the game, U18 boss Steve Potts and assistant manager Mark Phillips were both delighted to see the Hammers earn their place in the Barclays U18 Premier League Play-Offs, where they will travel to Manchester City.
"We said before the game that if we got through this game against Arsenal with a result then we would be there against Manchester City next week, which will be a tough test for the lads," said Potts. "That's what we want from the boys though, we want them to be tested and come through games getting results.
"Today was a hard test for us but I said after the game that Arsenal today would be a good test for us ahead of Manchester City next week," added Phillips." That will be another tough game next week and if we play well enough and make the final, it will be a third tough match that we will have to be up for."
The match details for the semi-final match against Manchester City are yet to be confirmed, but will be announced on whufc.com in due course.
Should the Hammers make the final, they will be up against either Southern group winners Tottenham Hotspur or Northern group runners-up Everton.
West Ham United U18: Howes, Knoyle, Burke, Onariase, Mavila, Pask, Nasha (Cullen), Makasi, Bywater, J Brown (Amoo), Parfitt-Williams (Gordon).
Subs not used: T Brown, Martins, Pike.