winning streak; string of wins
Used when someone keeps winning without a loss, often in sports or games. The っぱなし ending implies a continuous, uninterrupted state.
He's been on a winning streak this month.
This team has been winning straight since the season opener and hasn't lost yet.
Variant with 放し; less common but still seen.
Compound of 勝ち (the continuative form of 勝つ, 'to win') + っぱなし (a suffix indicating a state continues without change).