Co-owner Amanda Staveley and men's head coach Eddie Howe were among the 22,134 to watch Newcastle's comfortable victory.
Goals from Katie Barker, Brooke Cochrane, Georgia Gibson, and Beth Guy secured the win Becky Langley's side.
It was their first game at the historic St James' Park - and a record-breaking crowd came to see it.
It beat the highest gate in the Women's Super League so far this season, with 20,241 supporters that came to see Manchester United's 3-1 victory over Everton at Old Trafford in March.
The WSL attendance record of 38,262 was set in November 2019 by Tottenham when they played Arsenal in the north London derby.
Meanwhile, there were more people who watched Newcastle Women than Watford's defeat to Burnley at Vicarage Road, which was attended by 20,738 people.
Manager Langley said: "There are some fantastic female role models on the pitch and that's really what I want to focus on. The girls that were playing in front of 22,000 fans have inspired other females.
"We want equality, we want women to be shown in a fantastic light, and there are some great female footballers who are great girls off the pitch, but they're also fantastic players and a lot of young girls and boys are very inspired by that today."
A day after the Magpies' men went down 1-0 to Premier League title-chasing Liverpool in front of a crowd of 52,281 on Gallowgate, their women's side took to the same hallowed turf.
Such was the interest in the FA Women's National League Division One North clash with Alnwick Town, kick-off was delayed by 15 minutes to allow spectators queueing outside the stadium to be admitted.
On the night her consortium's takeover was confirmed in November last year, Staveley made a point of signalling her intention to invest in the women's team.
She said: "Personally, I'm a big fan of women's football - I'm a girl that never got to play football, so I'd like to see investment into Newcastle's women's team."