My suggestion would be a 3 week competition, quarter finals, semi's and final, That way everyone has something to play for and your current standing still comes into play.
Week 1: 1v8, 2v7, 3v6, 4v5
Week 2: 1v8 winner plays 4v5 winner, 2v7 winner plays 3v6 winner
Week 3: Grand final.