California Governor’s Mansion. | Photo: Lucy D’Mot

Nick Cahill contributed to this report from Sacramento; Martin Macias Jr. from Los Angeles County; Nathan Solis from Orange County; Bianca Bruno from San Diego County; and Nicholas Iovino from San Francisco.

SACRAMENTO – After rampant speculation that California’s ruthless “top-two” primary system could cause both Democrats and Republicans to be without candidates in critical races come November, party backers on both sides of the aisle woke to good news Wednesday.

>>See the complete local Santa Clarita Valley election recap here.

Despite clogging congressional contests with a horde of fresh and mostly unknown candidates, Democrats will have the chance to flip several Republican-held seats in districts won by Hillary Clinton in 2016.

Democratic candidates advanced in many vulnerable Republican districts in places like Los Angeles and San Diego, keeping alive the fabled “blue wave” this fall.

In northern San Diego, where Republican incumbent Rep. Darrell Issa is retiring, voters will have a choice between red and blue. Republican Diane Harkey won the primary with 25 percent of the vote and will face either Mike Levin or Sara Jacobs.

Pundits have identified the 49th Congressional District as one of the most vulnerable of California’s Republican-held seats. Issa won re-election in 2016 by the narrowest margin of any congressional race – less than 1 percent of the vote.

Activists from across California flocked to San Diego to help “flip the 49th.”

Christine Wei traveled nearly 500 miles from San Francisco to do neighborhood canvassing, phone banking and data entry. She says Trump’s election spurred her to become politically engaged.

“There’s urgency. Whether we get the numbers in the House this year will have a deep impact on getting things done at the federal level,” Wei said.

Farther north on Interstate 5, voters in Orange and Los Angeles counties also sent through a Democrat in a traditionally red congressional district.

Gil Cisneros narrowly held off Phil Liberatore for second place and will challenge primary winner Young Kim in the 39th Congressional District.

Democrats are also celebrating in the nearby 25th Congressional District after Katie Hill clinched second place in a district also held by a Republican incumbent.

The district – where Democrats outnumber Republicans by only 3.7 percent – has been marked as pivotal in the fight for control of the House.

According to election results, Hill, 30, barely edged her nearest rival by receiving 20 percent of the more than 78,000 votes cast. Incumbent Republican Steve Knight – seeking his third term in the office – received 53 percent of the vote with all 312 precincts reporting.

Hill, a former director of an LA-based homeless services nonprofit, thanked her supporters and volunteers “from the bottom of my heart” on Twitter Tuesday evening.

“I couldn’t be more proud of my team and all of the volunteers and supporters who have built this movement from the ground up,” Hill said. “Now, all we can do is celebrate the hard work put in the past 15 months!”

But Republicans didn’t come up empty-handed either: Voters sent a President Trump-backed gubernatorial candidate through to the November runoff.

San Diego businessman John Cox, buoyed by a recent spate of friendly tweets from Trump, finished second to Democrat Gavin Newsom in the chase to replace four-term Gov. Jerry Brown.

Cox bested third place-finisher Antonio Villaraigosa by a wide margin, creating a traditional Democrat-versus-Republican showdown.

“Great night for Republicans! Congratulations to John Cox on a really big number in California. He can win,” Trump tweeted.

Having a Republican candidate at the top of the ballot should jumpstart the state’s minority party and increase Republican turnout in other important races.

As with most elections in the nation’s most populous state, there were snafus, particularly in Los Angeles. More than 118,000 names were omitted from voting roster throughout the county in what officials called a printing issue.

Other high-profile races

Southern Californians still seething over a 2017 statewide gas tax increase recalled a Democratic state senator and replaced him with a Republican.

State Sen. Josh Newman, D-Fullerton, was recalled by more than half of voters in his district after a fierce opposition campaign that singled out his vote last year for Senate Bill 1, a $52 billion transportation fee package its foes disparagingly refer to as “the gas tax.”

California Republicans rallied behind the recall effort led by political action committee Reform California and former San Diego city councilman Carl DeMaio. Republican Ling Ling Chang will take over the rest of Newman’s term, set to expire in 2020.

The successful recall of Newman is a major blow to state Democrats since they no longer hold a two-thirds supermajority in the Senate.

Meanwhile, in San Francisco, the race to replace the late Mayor Ed Lee could drag on for days.

San Francisco Board of Supervisors President London Breed won 35.6 percent of first-choice votes, compared to 26 percent for her nearest rival, former state Sen. Mark Leno. But Leno surged ahead after another candidate, Supervisor Jane Kim, was eliminated and nearly 80 percent of her second-choice votes went to Leno.

A victory for either Breed or Leno would be historic: Breed would be the first black woman elected mayor in San Francisco and Leno would be the city’s first openly gay mayor.

Despite political drama among state Democratic brass at their recent convention, Tuesday’s election proved rank-and-file Democrats are still solidly behind U.S. Sen. Dianne Feinstein.

The Associated Press called the statewide race in Feinstein’s favor just 30 minutes after the polls closed. Feinstein, 84, received 43 percent of votes, well ahead of fellow Democrat Kevin de Leon with 11 percent, and appears headed to a sixth term.

For the second consecutive election, California Republicans will be locked out of the U.S. Senate race.

California Attorney General Xavier Becerra also breezed through the primary, winning easily over a recently retired Republican state judge. Becerra and Steven Bailey, former El Dorado County judge, differ on nearly every major issue including immigration and criminal justice reform.

Bailey, who has been charged by the state’s judicial watchdog with ordering criminal defendants to an alcohol monitoring company that employs his son and of taking prohibited event tickets, says he can overtake Becerra in November.

“We are going to keep fighting for the hard-working, tax-paying citizens and families of this state and we will win because we are focused on the issues and the problems you face every day,” Bailey tweeted.