A record attendance in the FA Women's Continental Tyres League Cup saw goals from Brooke Chaplen and Gemma Davison give Reading victory.
Both goals came in the second half and were enough to hand Reading a 2-0 victory in Group Two North in front of 4,835 fans at Leigh Sports Village.
Our previous cup round record was 2,110 when Reading met London Bees in 2017-18 while the competition’s best attendance was 4,214 in the 2016 final between Manchester City and Birmingham.
In United’s first home game of the new campaign, they had the better chances in the opening 45 minutes, with Jess Sigsworth going close to scoring early on but stabbing her effort wide.
United’s Kirsty Hanson was inches away from scoring, but her looping header hit the crossbar.
After the break, Reading’s Natasha Harding forced a smart near-post stop from Siobhan Chamberlain after she burst into the area.
Then Chaplen put Reading ahead - she was alert to the rebound from a saved Davidson strike and fired home from eight yards out. But shortly after defender Molly Bartrip was sent off for a second yellow card following a trip on Hanson.
And United almost stole a draw through Lauren James. But Davison had the final say, breaking from a United corner in added time, rounding goalkeeper Chamberlain and slotting past her to seal the win.
“The message at half time was that we needed to raise our level of performance, I don't think we started the game as brightly as we wanted to," said manager Kelly Chambers.
“At half time it was a case of reiterating that point and getting into the players to make sure they came out and delivered our game plan.
“In the second half, before the sending off we started to do that and that's why we've come away with this result today.
“The discipline and performance we showed to see the game out and hit them on the counter attack shows our experience and fitness levels.
“We have an international break now, and then Yeovil in our first league game of the season, and that gives us time to analyse this game.
“It was not perfect and we will reassess and make sure we have a good fortnight to prepare and pick up where we left off last season."
Manchester United (4-3-3): Chamberlain; Smith, Turner, Turner, Greenwood; Green (Palmer 60), Zelem, James, Arnot (Toone 78), Sigsworth, Hanson (Galton 67).
Subs: Bentley, Harris, Devlin, Roberts
Reading (4-4-2): Moloney; Bartrip, Pearce (Jane 73), Potter, Harding; Rowe (Woodham 90), Howard, Williams, Bruton; Davison, Chaplen (Allen 75).
Subs: Laws, Skeels.
Referee: Anthony Tankard