Ella Toone’s late strike sent Manchester United top of the Women’s Super League for the first time and ended Arsenal’s 100% start.
Jess Sigsworth chased down a loose ball and squared unselfishly for Toone, whose low shot went in via the post.
The Gunners had racked up 29 goals in their opening five WSL wins, but struggled to carve out chances.
Arsenal goalkeeper Manuela Zinsberger prevented further damage with a superb save from Christen Press’ low shot.
United were dealt a blow before kick-off with the loss of England forward Alessia Russo, who is to have surgery on a hamstring injury suffered in training on Friday.
But it was the Reds who created the better chances in a tight game as Joe Montemurro’s free-scoring side failed to create a significant goal threat or build any pressure for record scorer Vivianne Miedema to exploit.
United States international Tobin Heath shot wide of the near post and Toone fired over after a dangerous run from Leah Galton as the pressure built on the visitors.
Just as it seemed United would be frustrated, up popped Toone to seal a fifth straight league win for Casey Stoney’s side and maintain their unbeaten start to the campaign.
‘It looked high, reckless and dangerous’
Stoney felt Arsenal should have been reduced to 10 players early in the second half, after Lotte Wubben-Moy was only shown a yellow card for a lunging tackle on Galton.
“I couldn’t believe it was a yellow,” Stoney said. “I’m far away, so I’m only judging it from far away, but it looked high, it looked reckless and it looked dangerous.
“I wasn’t pleased with it as a tackle to be honest, so yes I did think there should have been a more severe punishment.
“[Beating Arsenal] is massive for the players’ mentally and belief – going into these games – that they can compete, they can win, because a winning mindset is really important.
“You have to have belief first, that you can do it, so I think they’ve got that now.
“I actually thought we created some really good chances, and I thought we were really positive in our attacks. If I’m honest, we were the worthy winners today, on the balance of the game.”
Arsenal boss Joe Montemurro: “We’re at fault. We were beaten by the better side tonight.
“It’s about ability, and doing what you need to do under the circumstances – we didn’t. They were better than us.
“They deserved to win over the 90 minutes and I can look at the tactical structures, the organisation and where we didn’t do things, but in the end, we weren’t able to cope with what Man Utd threw at us.”
Man Utd Women
- 12LaddSubstituted forZelemat 66′minutes
- 18HansonSubstituted forSigsworthat 45′minutes
- 77HeathSubstituted forStaniforthat 78′minutes
- 24PressSubstituted forJamesat 71′minutes
- 3Wubben-MoyBooked at 52minsSubstituted forMaierat 78′minutes
- 22SchnaderbeckSubstituted forMaceat 90′minutes
- 21GutSubstituted forRoordat 60′minutes
- 7van de DonkSubstituted forLittleat 59′minutes
Match ends, Manchester United Women 1, Arsenal Women 0.
Second Half ends, Manchester United Women 1, Arsenal Women 0.
Attempt missed. Vivianne Miedema (Arsenal Women) header from the centre of the box misses to the right. Assisted by Katie McCabe with a cross.
Corner, Arsenal Women. Conceded by Ona Batlle.
Attempt blocked. Katie McCabe (Arsenal Women) left footed shot from the left side of the box is blocked.
Attempt missed. Leonie Maier (Arsenal Women) left footed shot from the right side of the box misses to the left. Assisted by Kim Little.
Jackie Groenen (Manchester United Women) wins a free kick in the defensive half.
Foul by Kim Little (Arsenal Women).
Attempt blocked. Millie Turner (Manchester United Women) header from the centre of the box is blocked. Assisted by Katie Zelem with a cross.
Corner, Manchester United Women. Conceded by Ruby Mace.
Attempt blocked. Lucy Staniforth (Manchester United Women) right footed shot from outside the box is blocked. Assisted by Lauren James.
Foul by Lauren James (Manchester United Women).
Jill Roord (Arsenal Women) wins a free kick in the defensive half.
Substitution, Arsenal Women. Ruby Mace replaces Viktoria Schnaderbeck because of an injury.
Attempt blocked. Lauren James (Manchester United Women) right footed shot from outside the box is blocked. Assisted by Katie Zelem.
Corner, Manchester United Women. Conceded by Leonie Maier.
Attempt blocked. Leah Galton (Manchester United Women) left footed shot from a difficult angle on the left is blocked.
Attempt blocked. Ella Toone (Manchester United Women) right footed shot from outside the box is blocked.
Corner, Manchester United Women. Conceded by Leah Williamson.
Attempt missed. Lucy Staniforth (Manchester United Women) right footed shot from outside the box is too high.