They felt they 'had' the win/game 'sewn up'. [=they felt that they were certainly going to win]
She designs her own dresses and 'sews' in her free time.
He scored a touchdown that 'sewed up' the win/game.
(..) And the only excitement I've known is here with me now. So I'll go with you, and I won't whine, and I'll sew your socks, and I'll stitch you when you're wounded, and I'll do anything you ask of me (..)1969 Butch Cassidy and the Sundance Kid