You be the judge

Fourth round of a Scrabble tournament.

Both players have seven tiles on their rack in the final stages of the game. They check the bag and agree their is one tile left. One player puts down his word and takes the last tile. The next player goes and the first player, puts down his last four tiles and is out. He wins the game by seven points plus the tiles on his opponents rack. They finalize the score sheets and hand it in for inputting in the computer. As they are about clean up the board, the losing player says "Hey! There's another tile in here!" He calls over the judge and the judge says, the game goes on, the winning player has to take the last tile. The score sheet is returned and the game goes on. The last tile was a u and there's no place for it. The losing player now goes out and he wins by the last tile on his opponents rack, the u. Did the judge make the right call? Or was the handing in of the score sheet the end of the game?