The No. 2-seeded Barretto, a 17-year-old Tiburon resident, beat No. 9 Jenson Brooksby, 15, of Carmichael 6-4, 6-3. The No. 1-seeded Mayo, a Roseville resident who turned 16 last month, dominated No. 9 Ryder Jackson of Nicasio 6-1, 6-1.
In the quarterfinals of the girls 18s at UC Santa Cruz, No. 4 seed Carolyn Campana of Hillsborough ousted No. 5 Rachel Eason, the defending champion from Union City, 6-4, 6-2.
Also, No. 2 Katie Volynets, 14, of Walnut Creek dismissed No. 4 Jessi Muljat, 15, of Sacramento 6-3, 6-1. Volynets is ranked first nationally in the 14s.
Volynets avenged a 6-4, 7-5 loss to Muljat in the 16s final of the USTA International Spring Championships in Carson, Calif., in April.
No. 1 seed Herrick Legaspi of Sacramento and No. 3 Anushka Khune of Palo Alto won the boys and girls 12 titles, respectively, at the Sunnyvale Tennis Center.
The quarterfinals of the boys and girls 14s are scheduled for today at 11 a.m. at the Arden Hills Resort & Spa in Sacramento, followed by the semifinals at 3 p.m.
NORCAL JUNIOR SECTIONAL CHAMPIONSHIPS
At Natomas Racquet Club in Sacramento
SinglesPaul Barretto (2), Tiburon, def. Jenson Brooksby (9) Carmichael, 6-4, 6-3.
DoublesArjith Jayaraman, Gold River, and Andrew Ton (4), Milpitas, def. Siddharth Chari, Saratoga, and Randy Cory, Salinas, 6-4, 1-6 [11-9].
SinglesKeenan Mayo (1), Roseville, def. Ryder Jackson (9), Nicasio, 6-1, 6-1.
DoublesSam Gibson, Chico, and Stevie Gould (4), Corte Madera, def. Ryder Jackson, Nicasio, and Zachery Lim (8), Fairfield, 4-6, 6-3, 6-3.
At Sunnyvale Tennis Center
SinglesHerrick Legaspi (1), Sacramento, def. Raghav Jangbahadur (4), Palo Alto, 6-2, 6-0.
DoublesJohn Kim, Sunnyvale, and Herrick Legaspi (1), Sacramento, def. Liam Carpenter, Greenbrae, and Patrick Toman (3), Pleasant Hill, 6-2, 6-1.
SinglesAnushka Khune (3), Palo Alto, def. Georgia Beard (1), Santa Rosa, 6-3, 6-2.
DoublesAnushka Khune, Palo Alto, and Madison Weekley (2), Alamo, def. Martina Marica, San Jose, and Kamila Wong (3), Palo Alto, 6-0, 6-2.