The party that governed Mexico for seven decades won a crushing victory Sunday in the most important state race before next year's presidential elections. But another state vote was closer than expected.

Victory in big Mexico state bolsters the Institutional Revolutionary Party, or PRI, but it does not guarantee a return to the presidency the party lost in 2000: Its potential candidates all trail Mexico City Mayor Andres Manuel Lopez Obrador in the polls.

With 73 percent of the vote counted, the PRI's Enrique Pena Nieto had 47 percent to 25 percent for Ruben Mendoza of President Vicente Fox's National Action Party and 24 percent for Yeidckol Polevnsky of Lopez Obrador's Democratic Revolution Party.

Pena vowed to heal the wounds of the campaign and praised Mendoza for telephoning to concede defeat. But Polevnsky said he would challenge the election, alleging the PRI vastly overshot spending limits.

While the PRI celebrated in Mexico state, it was in unexpected danger in the small western state of Nayarit, where pre-election polls showed the PRI with a double-digit lead to recapture a state it lost six years ago.

Both the PRI and Democratic Revolution said their own exit polls Sunday showed they had won. Independent exit polls by the two television networks showed the race too close to call.

With 20 percent of Nayarit's official returns in, the PRI's Ney Gonzalez led with 46 percent to 41 percent for Miguel Angel Navarro of Democratic Revolution and 7 percent for National Action's Manuel Perez.

The election day was another dose of bad news for Fox's party, which had run well in Mexico state in earlier elections and which now shares the governorship of Nayarit.

The only other gubernatorial election before the July 2006 national vote is a September race in the mid-sized northern state of Coahuila -- where the PRI also is favored to win.

Enrique Pena Nieto of the Institutional Revolutionary Party campaigns in Cuautitlan Izacalli. Once an obscure candidate, he will become governor of Mexico's largest state.