By Jamie Spencer & Emily Keogh Manchester United manager Marc Skinner is adamant that his team have no choice but to keep fighting in the WSL to make up a ten-point gap that has opened to leaders Chelsea. United fell to a 3-1 defeat at Stamford Bridge on Sunday that, having gone within a whisker of winning the title last season, now leaves them fourth and struggling to contend once again. Chelsea are the only domestic side that United have faced in their short history, beginning with a reformed first-team in 2018, and have not yet beaten. Skinner sees the difference between the club and insist…