Arsenal tightened their grip on a return to the Champions League with a 3-1 victory over Manchester United in front of a Women's Super League record sell-out at the Emirates Stadium.
The Gunners, who sold 60,160 tickets for the lunchtime contest, were gifted an early goal when Katie McCabe's corner deflected in off Geyse.
Another error allowed Cloe Lacasse to nod in a second before Kim Little's spot-kick made it three before the break.
Lucia Garcia clawed one back in stoppage time but it was little consolation for fourth-placed United, now seven points adrift of qualifying for a second European campaign with just eight games remaining.
Arsenal boss Jonas Eidevall made six changes, dropping forward Alessia Russo to the bench while her England team-mate Leah Williamson was absent due to what the club described as a "minor hamstring injury" less than a month after returning from the anterior cruciate injury that led to a nine-month spell on the sidelines.
It was a nervy start for the hosts, who conceded a free-kick in the fourth minute, spilled by Arsenal goalkeeper Sabrina D'Angelo, before the Gunners got out of danger, winning their first corner in the seventh minute but seeing it punched away by England international Mary Earps.
However, Arsenal went ahead after 10 minutes when their second corner, taken by McCabe, first deflected off the unfortunate Geyse inside the six-yard box and then rolled through the legs of a helpless Maya Le Tissier and over the line.
Marc Skinner's side struggled to get anything started in reply, giving away a free-kick in a dangerous position that Beth Mead blasted well wide after going directly for goal, while United could not take advantage of a corner after Ella Toone's sharp effort took a deflection off Steph Catley.
The Gunners' second in the 35th minute initially looked to be a missed chance when Victoria Pelova picked out Stina Blackstenius in front of the United goal but her squared pass skipped past the Sweden international towards Katie Zelem, who attempted to hook clear.
Instead, the United captain lofted the ball in the direction of Lacasse, who happily headed home her third league goal, three days after bagging a brace in their Conti Cup win over London City.
Things went from bad to worse for the visitors when Gemma Evans brought down Mead and Little coolly converted, sending Earps the wrong way with a low finish.
Nikita Parris missed an opportunity to claw a goal back after the restart, directing a pair of headers wide, before the Gunners responded, Blackstenius once again taking advantage of some loose defending to intercept Hannah Blundell's pass back to Earps, who managed to parry away the attempt.
Mead was denied by the post twice in quick succession, her first attempt a rocket from the right that would have likely beaten Earps but instead clipped the inside of the woodwork before bouncing out.
D'Angelo comfortably saved Parris' effort at the near post before surviving a scramble, with Catley then replaced by Caitlin Foord as both bosses made changes.
Just as it appeared the hosts would wrap up a clean sheet, D'Angelo came off her line to meet a late United corner but Garcia pounced in the sixth minute of added time.
