RIO DE JANEIRO (Reuters) - Current men's volleyball Olympic champions and medal favorites United States won the chance to defend their title by securing a quarter-final slot with a 3-0 victory over Mexico on Monday.

The U.S. has clawed back from the brink of elimination after losing its first two games to Canada and Italy and began its comeback with a stunning 3-1 win over hosts Brazil.

United States overwhelmed the last-placed Mexicans in straight sets (25-23, 25-11, 25-19) in their last preliminary game and is guaranteed a place in the quarter-finals.

The Americans were tied with France, Canada and Brazil with six points before Monday's victory, but Brazil must play France and Canada face group leaders Italy on Monday night.

"I still don't think we can exhale. I don't know what position we're in really. I know we had to win," outside hitter Taylor Sander said after the game.

After upsetting Brazil, U.S. overpowered France in four sets on Saturday, putting the Americans on a roll for an easier encounter with Mexico.

"The big challenge was having such emotional matches the previous two and being able to summon those emotional reserves and come out and to bring that again," said U.S. coach John Speraw.

(Reporting by Anthony Boadle; Editing by Bill Rigby)