Mexico's former ruling party claimed victory Monday in this border city's mayoral race with a controversial candidate who overcame a double-digit deficit in pre-election polling.

The Institutional Revolutionary Party, or PRI, also claimed victory in the governor's race in the southern state of Oaxaca, though the challenger promised to contest the outcome of Sunday's vote.

Wins in Oaxaca and Tijuana would boost morale in the PRI, whose 71-year hold on the presidency ended in 2000 with the election of Vicente Fox. They also would help the presidential chances of the PRI's national leader, Roberto Madrazo, whose party remains Mexico's largest and best-organized.

With 96.5 percent of the vote counted in Tijuana, PRI candidate Jorge Hank Rhon was one percentage point ahead of Jorge Ramos of Fox's National Action Party.

Hank Rhon came back from a double-digit deficit in opinion polls by spending heavily and treating would-be voters to parties on the grounds of his Tijuana racetrack.

Hank Rhon has estimated his wealth at about $500 million, part of it inherited from his late father, PRI patriarch Carlos Hank Gonzalez, and part built on profits from a nationwide sports betting network.

In 1988, two of his security guards were convicted of killing a Tijuana journalist who had reported on corruption and had investigated Hank Rhon.

Fox's party has held the Tijuana mayor's office for 15 years. It is a now a key battleground in the PRI's efforts to regain power.

The PRI also claimed a contested victory in Oaxaca, a party stronghold challenged by a coalition that included Fox's party.

With 90 percent of the ballots counted in Oaxaca, the PRI's Ulises Ruiz had 47 percent and opposition candidate Gabino Cue had almost 45 percent. Cue charged that the official returns had been manipulated and vowed a challenge.

In the state of Aguascalientes, the National Action Party candidate easily defeated a PRI challenger in Sunday's only other gubernatorial race.