In January 2014, Chelsea announced the double transfer of Flaherty and Katie Chapman from Arsenal. The move reunited both players with coach Emma Hayes, who previously worked at Arsenal. Hayes said of Flaherty: "Gilly is the best uncapped player in the country. She will become a bedrock for club and country as she has all the hallmarks of a top class player." Flaherty's first season with the team ended in disappointment, as they lost the league title to Liverpool on the final day of the campaign. 2015 proved much more successful, yielding the club's first ever major trophy – won at Wembley Stadium in the 2015 FA Women's Cup Final. In October 2015 Chelsea's 4–0 win over Sunderland secured the FA WSL title and a League and Cup "double".
