By Dave Graham
MEXICO CITY—The second-placed contender in Mexico’s presidential race won the opening televised debate of the campaign on Sunday night, a telephone survey found, after the front-runner came under relentless attack from competitors.

MEXICO CITY—The second-placed contender in Mexico’s presidential race won the opening televised debate of the campaign on Sunday night, a telephone survey found, after the front-runner came under relentless attack from competitors.