Sam Quek scored the winning goal seven minutes from time as England beat South Africa 2-1 in the final of the London Cup in the Olympic Park.
The Reading defender fired home following a penalty corner in a tight second half to settle the match.
Nicola White gave England a first-half lead by flicking in following another penalty corner but Jade Mayne levelled before the break.
England's men also won the tournament, beating Ireland in a penalty shootout.
The hosts won 4-2 on penalty flicks after a 2-2 draw.
Both England teams will compete at the Commonwealth Games in Glasgow later this month.
Women's captain Kate Richardson-Walsh said her side had taken "some small steps forward".
She added on Sky Sports: "We knew this would be a tough time, we were looking to build confidence and have done that."