If you lose a game during your win streak, you will have the opportunity to save it. Saving your win streak will erase your lost game and allow you to continue with your win streak. 

However, if you choose not to save your win streak, you will restart at 0 wins and need to begin a new win streak. Please keep in mind that if you quit before the end of a game or get disconnected, you will not be able to save your win streak.