San Mateo Supervisor Rich Gordon is on his way to Sacramento after voters in San Mateo and Santa Clara counties elected him Tuesday to replace outgoing Assemblyman Ira Ruskin in the 21st District.

Gordon, who defeated former Palo Alto Mayor Yoriko Kishimoto and Menlo Park venture capitalist Josh Becker in the Democratic primary in June, convincingly defeated his Republican challenger Greg Conlon Tuesday in the heavily Democratic district.

With most of the results counted, Gordon received about 60 percent of the vote in Santa Clara County and about 62 percent in San Mateo County. Conlon received 36 percent and 33 percent of the vote in the two counties, respectively.

Gordon's victory was a gleam of good news for local Democrats on a day when the party took a political pounding and lost its majority in the U.S. House of Representatives. At about 9:30 p.m., a cautiously optimistic Gordon thanked his supporters in the party's Palo Alto headquarters and said he looked forward to the major challenges in Sacramento, which he called a "strange and insidious place."

"I want you to know that I understand this will be the most difficult job I've ever taken on," Gordon said.

Ruskin said Tuesday that he plans to run for the seat currently occupied by state Sen. Joe Simitian, a Palo Alto Democrat whose term expires in two years. Both Ruskin and Simitian stopped by the party headquarters Tuesday evening to congratulate Gordon and console the party faithful over the national results.

In his victory speech, Gordon focused on the good news for Democrats in the election results, particularly the voters' rejection of Proposition 23, which would have suspended a California law aimed at restricting greenhouse gas emissions. The proposition was largely funded by two Texas oil companies, Tesoro and Valero.

"Just as our beloved Giants beat Texas, we gave the boot to Texas oil companies and defeated Proposition 23," Gordon told his supporters.