Girls' soccer team goes undefeated winning their league - which they played entirely against only boys' teams

Plymouth-based SB Frankfort Under-12 Girls have completed a remarkable league and cup double.

(CNN)An all-girl soccer team has displayed real girl power by winning a league and cup double -- which they played in its entirety against only boys' teams -- completing the season without a defeat.

On Sunday, Plymouth-based, nine-a-side SB Frankfort Under-12 Girls beat Morley Rangers Juniors to win the Argus Cup in Torpoint, Cornwall.
They had previously topped the Argus League by winning 14 out of 18 games against boys' teams.
"I was elated for the girls, four years we have been playing boys for the sole purpose of improving and learning. So to win the double this year has been incredible," head coach James Brown Tunnell and assistant coach John Preston told CNN Sport.
    "At the start of the season we didn't want to set targets, we knew we had a strong, talented group of girls that were ready to compete and work their hardest," Tunnell and Preston continued.
    "As the season went on it was clear we had a chance to win the league and the cup. However the girls needed to stay grounded and just focus on playing their game."
    "After we just said to the girls, they have been fantastic all season long. The pressure has grown throughout the season and they have dealt with it superbly, we couldn't be more proud of them."
    Next season, the SB Frankfort girls will play in a 11-a-side boys' league.
      Tunnel believes it's the first time a girls grassroots football team has won a league and cup double competing against boys.
      CNN has reached out to England's Football Association for confirmation and comment.