last stand

1. A final defensive military effort against overwhelming odds, typically done in order to defend a particular location against invading forces. Their platoon made a last stand in an ultimately futile attempt to prevent the base from falling into enemy hands.

2. By extension, any final effort to defend something or oppose someone in order to succeed or maintain one's position. The senators seem to be making a last stand in the face of huge losses in the upcoming election, trying to push through as many policy changes as possible to satisfy their constituents while they still can. Behind three games to zero and facing another championship defeat, the team put up an incredible last stand, somehow managing to win four games in a row and secure the title.