Inspired by Bukayo Saka, Arsenal scored five goals in a wild first half at West Ham before settling for a 5-2 win that lifted the team into second place in the English Premier League.
Saka was one of five different scorers for Arsenal in the day's late game at the Olympic Stadium on Saturday and also had a hand in three goals, by Gabriel, Leandro Trossard and Martin Odegaard.
Kai Havertz netted the other goal for Arsenal in its biggest league victory this season.
Since returning from the international break, Arsenal have beaten Nottingham Forest 3-0 in the Premier League, Sporting Lisbon 5-1 in the Champions League and put another five goals past West Ham.
The prolific run has coincided with the return to fitness of Odegaard, Arsenal's playmaker and captain who missed two months with an ankle injury.
Arsenal trimmed the gap to Liverpool to six points ahead of the leader's home match against beleaguered Manchester City on Sunday.
All of the goals in the match were in the first half. It's just the fourth time since the Premier League began in 1992 that seven goals were scored in a game before halftime.
Meanwhile, a day after being hired as Leicester manager, Ruud van Nistelrooy witnessed at first hand the scale of his task to keep the team in the Premier League.
Leicester were beaten at Brentford 4-1 on Saturday, with Van Nistelrooy sitting in the stands rather than in the dugout. He officially takes over as coach on Sunday after arriving as the replacement for the fired Steve Cooper.
Leicester manager Ruud van Nistelrooy.
Ruud van Nistelrooy watches on as his new Leicester side were trounced at Brentford. (AP PHOTO)
Kevin Schade scored a hat trick and Yoane Wissa also netted for Brentford, who had to come from behind after Facunda Buonanotte's 21st-minute opener.
Van Nistelrooy, the former Manchester United and Real Madrid striker, will begin his first full-time managerial role in English football with Leicester in 16th place in the league and just one point above the relegation zone.
History was made when Justin Kluivert converted a trio of penalties — in the third, 18th and 74th minutes — for Bournemouth in their 4-2 win at Wolves, something that has never been achieved before in a league game.
Newcastle lost Sweden striker Alexander Isak to a hip injury midway through the first half and then their lead in the fourth minute of stoppage time in a 1-1 draw at Crystal Palace.
Daniel Munoz scored the late equaliser to lift Palace out of the bottom three on goal difference.
Chris Wood smashed a penalty down the middle for his eighth goal of the season to earn Nottingham Forest a 1-0 win at home to Ipswich.