RIO DE JANEIRO — The most entertaining World Cup in a generation comes down to a final match that pits the planet's best player against the tournament's best team. Lionel Messi will lead Argentina out against Germany at Maracana Stadium on Sunday for a game that will define careers, cement legacies and be watched by a global audience of about a billion viewers. And it's a matchup that means more to both sides than just a chance to lift one of the most hallowed trophies in sports.