Alessia Russo sealed a remarkable comeback in stoppage-time as Manchester United stunned Arsenal 3-2 to inflict a first defeat of the season on the WSL leaders.
Arsenal were five minutes away from a seventh-consecutive victory after second-half goals from Frida Maanum (46) and Laura Wienroither (73) cancelled out Ella Toone's first-half opener (39).
But Miller Turner's equaliser (85) drew United level before the majority of the 40,064 fans inside the Emirates Stadium were silenced when Russo headed the winner in off the underside of the crossbar (90+1).
United's sixth and biggest victory of the season lifts them level on 18 points with leaders Arsenal, who tasted defeat for the first time.
Man Utd late-show ends Arsenal's perfect start at Emirates
The Gunners had won their first six games of the season by an aggregate score of 18-1 but appeared gripped by first-half stage fright as another landmark WSL crowd packed into the Emirates.
United grew in stature with each passing minute, with goalkeeper Manuela Zinsberger called into action to deny Toone before the Gunners stopper unconvincingly flapped at a cross and had Beth Mead to thank for clearing the danger.
Zinsberger would not get away with another one, with Toone improvising brilliantly to turn in United's opener after the goalkeeper failed to deal with a cross from the right six minutes before half-time.
United were deserved leaders at the break but that lead would last just 34 seconds, Maanum's heavily deflected long-range strike fortuitously hauling Arsenal back on level terms.
Vivianne Miedema made her much-anticipated return to first-team action and was at the heart of a late Arsenal surge which culminated in the Gunners taking the lead for the first time.
Katie McCabe's stunning cross from the left - the best of the game - found the late-arriving Wienroither in the area and she unerringly dispatched first time to give Arsenal a lead they thought would secure another victory.
But United had other ideas. Five minutes from time, Turner met captain Katie Zelem's cross and planted an equaliser past Zinsberger in the Arsenal goal, before Zelem's corner reached Russo and she completed a dramatic turnaround in added time.
Arsenal are in Champions League action on Thursday as they face Juventus in Italy with the Gunners looking to consolidate top spot in Group C. Jonas Eidevall's side then return to WSL action on Saturday December 3 as they host Everton.
Manchester United have a two-week break with Marc Skinner's side next in action on Saturday December 3 as they host Aston Villa in the WSL.