Marshall - nicknamed the Silent Assassin - was a guest at Newcastle United Women's 2-1 Vitality Women's FA Cup second round win against Barnsley Women, which was watched by 28,565 in a new record for the competition outside of a final.
The former WBO female middleweight champion, who hails from Hartlepool, fought Claressa Shields at a sold-out O2 Arena last month - the first time two female boxers headlined at a major venue in the United Kingdom and a bout which was top of the bill at the first all-female boxing card in the United Kingdom.
And although she ultimately lost on points to Shields, who became the undisputed middleweight world champion, more than two million tuned in to a thrilling fight - Sky's biggest ever audience for a live women's sport event.
She was introduced to the crowd at half time on Sunday, along with Aran Embleton, a lifelong Newcastle fan who became the first woman from the North East to play for England in 2001, and players from the Newcastle Eagles Women basketball team.
"Newcastle definitely get behind their women - I'd like to see all the clubs do that," Marshall told nufc.co.uk. "It's great that Newcastle, who I call my football club, is backing female sports.
"It's flying - in football, the England women, you had the rugby and obviously the boxing. It's going in the right direction."
A rematch between Marshall and US-born Shields looks likely - particularly as Marshall previously inflicted the only defeat that Shields, the self-proclaimed 'GWOAT' (Greatest Woman of All Time), has suffered during her professional and amateur career.
And just like women's football, female boxing is getting bigger all the time with Marshall, who as an amateur won gold at the 2012 World Championships to become the first British female world champion, one of its leading stars.
"It's amazing," she said. "Obviously I never got the result (against Shields) but just from the response, I feel like I've won. It's crazy - I can't really describe it, but just how much people got behind me, the support from the North East especially, was amazing."
Sunday's attendance surpassed the figure of 22,134 - an attendance record for a league match at all levels of the women's game in the UK last season - when Newcastle United Women played at St. James' Park for the first time in May, beating Alnwick Town Ladies 4-0.
And the crowd was treated to a stirring comeback from a goal down, with spectacular strikes from Georgia Gibson and Sharna Wilkinson earning United a place in the third round, where they will face Wolverhampton Wanderers Women next month.
So can Marshall - whose last fight not only packed the O2 Arena but was screened in 150 countries worldwide - see a day in the near future when the Magpies' famous stadium is sold out for a Newcastle United Women match?
"I don't see why not," she insisted. "Everyone's getting involved in women achieving and stuff like that, so I can't see why not."
