Sanchez is one of the four remaining contestants in the Fox program after wowing the judges at times but needing their intervention once to avoid being kicked off the show in a vote by viewers.
In a tongue-and-cheek message to the media, Sanders urged that San Diegans unite behind the Eastlake High School student.
"As evidenced by the current mayoral race, San Diego is a city whose residents possess the full spectrum of political opinions,'' Sanders said. "But even Bonnie Dumanis, Nathan Fletcher and the two other mayoral candidates whose names I can't remember would agree on this much -- Jessica Sanchez is far and away the best performer on this season's `American Idol.'''
The mayor was referring to the main candidates to succeed him -- Dumanis, the district attorney; Fletcher, an assemblyman; Councilman Carl DeMaio; and Rep. Bob Filner, D-San Diego.
After Wednesday night's show, broadcast on FOX 5 at 8 p.m., viewers will vote to reduce the field to three performers.
Sanchez, 16, is the second recent contestant from San Diego County to make it deep into the "Idol'' competition. Mt. Carmel High School alumnus Adam Lambert rocked his way to a runner-up finish three years ago.
Whether or not she wins, Sanchez will reportedly perform the national anthem and the song "The Prayer'' at the PBS National Memorial Day Concert on the west lawn of the Capitol building inWashington, D.C.
Last month, Chula Vista Mayor Cheryl Cox began urging residents of that city to rally behind the hometown favorite.
It was also reported this week that a Catholic priest in the Philippines has asked Filipinos worldwide to pray for Sanchez, whose mother is a Filipina.