Harvard-Westlake High senior Ryan Thacher is the No. 1-ranked junior in Southern California and ranked No. 3 in the nation. Standing 6-foot-3, and possessing a booming serve and the ability to hit every shot in the book, the left-hander has all the physical tools needed to make it big.

The one thing lacking on the 18-year-old's résumé is experience, a weakness that surfaced during the teenager's quarterfinal match against 24-year-old Lester Cook in the Men's Open division of The Ojai Valley Tennis Tournament on Friday.

Cook is ranked No. 376 on the ATP Tour and has played against some of the game's best players. He used that experience to his advantage during the 212-hour match with Thacher.

"He's 18 and he's going to be a great player, but experience played a little role there," Cook said after his 6-3, 7-6 (2) victory. "I think, especially in the tiebreaker, my experience helped me."

Cook, who is the defending champion and the No. 2 seed, will be joined in this morning's semifinals by the other three top seeds. Brian Wilson, the No. 1 seed, defeated Nina Roshman 6-3, 6-3 in their quarterfinal match.

Wilson will meet No. 4 seed Cecil Mamiit, who defeated fan favorite Alex Vlaski 6-7 (4), 6-4, 6-1, to advance.

Cook will take on Ojai resident Travis Rettenmaier in a rematch of last year's Open final. The former Camarillo High standout defeated Jamil Al Agba 7-5, 3-6, 6-4. Both semifinal matches will start at 9:30 a.m. at Libbey Park.

Cook knew how tough Friday's match was going to be because he practices with Thacher at Mountain Gate Tennis Club.

As the defending champion, most players would expect to earn the top seed, but Cook said he didn't feel slighted about not being given the honor.

"One or two (seed), there is no huge difference," Cook said. "I think they go strictly off the current rankings. I still get my (free) room at the (Ojai Valley) Inn, so everything is good."

Veterans set for doubles: Former Pierpont Racquet Club tennis pro Tracie Currie and the club's current pro, Nancine Haywood, are teaming up to play in the Women's Open Doubles, which start today.

Currie and Haywood will square off with the top-seeded team of Judith Devera and Dianne Matias at 12:30 p.m. at the Ojai Valley Inn.

Currie has seven Ojai doubles titles to her credit.

Despite battling plantar fasciitis for more than a year and having an appendectomy three weeks ago, she decided to give it a go.

"My racquet is older than some of the girls we might be playing against," Currie said.

Community colleges: Matthias Muster had a day to remember at the Oxnard Tennis Center. Muster, who plays for Ventura College, upset No. 5 seed Christian Isip of Cypress in a match that lasted 3 hours and 20 minutes. The score of the third-round match was 5-7, 7-6 (4), 7-6 (3).

Unfortunately, Muster had nothing left later in the day for his round-of-16 match and he went down to Tiago Hayashi of College of the Desert, 6-2, 6-1.

Ventura's Hassan Abbas, seeded No. 6 in men's singles, won two matches to advance to the quarterfinals. Abbas defeated Jason Wall of Cerritos 6-0, 6-1 in the third round and Grossmont's Joao Toledo 6-3, 6-3 in the round of 16.

In women's singles, VC's Ally Limon won her third-round match, but lost in the round of 16 to No. 1 seed Erina Hung 6-3, 6-2. Sarah Gifford of VC lost in the third round to Courtney Petero 6-1, 6-3.

Division III men: Paul Wetterholm of Cal Lutheran got off to a good start with a first-round win, but was unable to advance any further. Wetterholm defeated Jeff Hammond 6-4, 6-3, but then lost a tough three-setter to Jeff Fong 6-7 (5), 7-5, 6-1.

CLU's Ryan Lassila lost his first-round match to Aron Ouye 7-6 (4), 4-6, 6-4.