The Manchester United Women captain showed great movement to get free from a clever low corner by Toni Duggan and produced a neat finish from 10 yards to find the net on 58 minutes.
Manchester City duo Steph Houghton and Ellen White had earlier given the Lionesses a 2-0 lead at half-time in an incident-packed game in Valenciennes.
Sunday’s last-16 tie at Stade du Hainaut wasn’t without controversy involving the Video Assistant Referee (VAR), which has been the subject of intense scrutiny throughout the tournament.
Cameroon could have been reduced to 10 players from as early as the fourth minute when Yvonne Leuko elbowed Nikita Parris but Chinese referee Qin Liang opted to show her a yellow card, with no VAR intervention.