Greenwald, the fifth seed and 2009 champion, dismissed William Casas of Rancho Mission Viejo 6-0, 6-2 today. Bax, seeded ninth, outclassed Thomas Cooper of Rancho Palos Verdes 6-1, 6-2.
Also advancing to the quarterfinals with easy victories were top-seeded Tony Bujan of Tustin, third-seeded Oren Motevassel of San Jose, ninth-seeded David Smith of San Francisco and unseeded Shibu Lal of Novato.
Bujan, a three-time All-American at TCU in the early 1990s, is trying to become the first man to win the title three years in a row since USC men's coach Peter Smith (2005-07).
Motevassel, who reached a career-high No. 161 in the world in 1997, won the crown in 2011 and 2012.
Fanny Gamble of San Rafael and Zeynep Aynaci of San Francisco moved into the women's quarterfinals. Gamble eased past Christine Anzai of San Diego 6-2, 6-2, and Aynaci advanced by walkover.
Aynaci will take on Jennifer Dawson, the third seed and 2011 champion, of Carlsbad. Gamble will meet fourth-seeded Mercedes Michel of New York.
Top-seeded Amy Frazier of Rochester, Mich., thrashed Cynthia Delgado of La Jolla 6-1, 6-0. Frazier, a two-time Grand Slam singles quarterfinalist, climbed to a career-high No. 13 in 1995. She is playing in her first tournament since retiring from the pro tour in 2006.
USTA NATIONAL 40 HARD COURT CHAMPIONSHIPS
In La Jolla, Calif.
(Northern California results only)
Second roundJeff Greenwald (5), San Anselmo, def. William Casas, Rancho Mission Viejo, 6-0, 6-2.
Leon Bax (9), Mountain View, def. Thomas Cooper, Rancho Palos Verdes, 6-1, 6-2.
Oren Motevassel (3), San Jose, def. Christopher Criblez, Laguna Hills, 6-0, 6-1.
Leonardo Bravo (9), San Diego, def. Joshua Prager, Yuba City, 6-2, 6-3.
Greg Failla, Ramona, def. Nicolas Chasseray (9), San Francisco, 6-1, 6-3.
Shibu Lal, Novato, def. Octavian Popaluca, San Diego, 6-0, 6-0.
David Smith (9), San Francisco, def. Leonardo Goldstein, San Diego, 6-0, 6-3.
Second roundZeynep Aynaci, San Francisco, def. Maria Nunez, San Diego, walkover.
Fanny Gamble, San Rafael, def. Christine Anzai, San Diego, 6-2, 6-2.
Arthur Hernandez, Huntington Beach, and Carsten Hoffmann (4), Newport Beach, def. Jesse Ponwith, Scottsdale, Ariz., and David Smith, San Francisco, 6-4, 4-6, 7-5.Marcio Carlsson and Igor Santana, Las Vegas, def. Dave Kuhn, Elk Grove, and Joshua Prager, Yuba City, 6-1, 6-4.
Leon Bax, Mountain View, and Nicolas Chasseray (2), San Francisco, def. William Casas, Rancho Mission Viejo, and Brian Matek, Placentia, 6-2, 6-4.
Second roundJenny Keller, La Jolla, and Conan Lorenzo, La Mesa, def. Cynthia Polansky, Mill Valley, and Brian Denny, Chico, 6-2, 6-2.
Fanny Gamble, San Rafael, and Kosei Ohno, Kirkland, Wash., def. Cynthia Delgado, La Jolla, and Octavian Popaluca, San Diego, 6-4, 7-6 (1).
Christine Anzai, San Diego, and Manuel Ortiz, La Jolla, def. Lisa Traylor, Laguna Hills, and Shibu Lal, Novato, 6-2, 2-6, 6-4.
Maria Nunez, San Diego, and Olivier Tonnerre, Mill Valley, def. Allison Golden, Philadelphia, and Robert Bull, Phoenix, 6-2, 6-3.
Zeynep Aynaci and Nicolas Chasseray, San Francisco, vs. Jeff Ray and Monica Sweet, San Diego, late.