The Gunners achieved their fourth successive victory after an important victory over Liverpool, specifically 3-1, in the last stage, and before that, Nottingham Forest (2-1) and Crystal Palace (5-0).
Frenchman William Saliba (32nd), Bukayo Saka (41st from a penalty kick and 63rd), Brazilian Gabriel (44th), Belgian Leandro Trossard (45+2) and Declan Rice (66th) took turns scoring goals.
This is Arsenal's biggest win outside its home stadium in the league since 1935 (7-1 over Aston Villa), and it avenges its defeat at home to its neighbor 0-2 in the nineteenth round on December 28 last.
It is also the biggest loss for West Ham at home in the history of meetings with its rival.
West Ham suffered its second loss in a row in a series of seven consecutive matches in all competitions in which it did not taste victory, and its score froze at 36 points in eighth place.
Trossard came close to opening the scoring with a shot from inside the area, which French goalkeeper Alphonse Areola excelled in clearing (23).
The defenseman, Saliba, took advantage of a corner kick taken by former West Ham captain and midfielder Rice, scoring the first goal with his head (32).
Saka wasted a great opportunity to add a second goal with a header that passed near the right post (35), before he himself received a penalty kick after being obstructed by Areola, scoring his team’s second goal and his ninth in the league this season (41).
The Gunners continued their pressure and were able to score the third goal with a third free kick through the second defenseman, Gabriel, with a header after a cross from Rice (44).
This is the first time that Rice has scored two goals in one match in the league, noting that he played 204 matches in the “Hammers” shirt.
Trossard wrote his name on the scorers list with a beautiful goal after a coordinated attack that reached Norwegian captain Martin Odegaard, who played it to the Belgian and the latter placed it in the roof of the left corner of the goal (45+2).
Before the end of the first half, hundreds of West Ham fans left the stadium in anger at the big score and the poor performance.
Scottish West Ham manager David Moyes made two substitutions at the beginning of the second half in order to revitalize his team, but Saka ended any hope for the home team to return by scoring the fifth, taking advantage of a pass from Odegaard (63).
West Ham's collapse continued when Rice scored a sixth goal, his third in the league with his new team (66), refusing to celebrate.
Aston Villa, fifth, will play Manchester United, sixth, later, while the stage concludes on Monday with a meeting with Crystal Palace (15) and Chelsea (11).