Democratic challenger Harley Rouda increased his lead to 2,682 votes early Wednesday over incumbent Rep. Dana Rohrabacher (R-Costa Mesa) in the race for the 48th Congressional District seat.

With all precincts reporting, Rouda had 91,750 votes, or 50.7%, to Rohrabacher’s 89,068.

The contest for the 48th District has been seen by Democrats as their best chance yet to unseat the nearly 30-year incumbent while aiding their drive to gain control of the U.S. House of Representatives.

The 48th runs from Seal Beach to Laguna Niguel and stretches east into parts of Westminster and Garden Grove. It also includes Huntington Beach, Costa Mesa, Fountain Valley, Newport Beach, Aliso Viejo and Laguna Beach.

At his Election Night party Tuesday, Rohrabacher stood onstage at Skosh Monahan’s in Costa Mesa next to an old surfboard that read, “Give me liberty or give me surf,” and called his bid for reelection a race of “David against Goliath.”

A supporter shouted back, “Dana versus Goliath!”

Rohrabacher told supporters that Democrats had spent wildly to try to defeat him.

“We’ve had billionaires coming from outside,” he said. “We’ve taken on Goliath. We’ve taken on billionaires.”

Rouda, a lawyer and real estate businessman from Laguna Beach, qualified for Tuesday’s ballot by edging fellow Democrat Hans Keirstead by 125 votes for second place in the June primary, behind Rohrabacher.

In a debate last month, Rohrabacher, first elected in 1988, accused Rouda of being soft on illegal immigration, while Rouda claimed Rohrabacher “wants to deport everyone who is here undocumented.”

Rouda also accused Rohrabacher of being soft on Russia, while Rohrabacher said, “We should cooperate with Russia now that it’s no longer our major threat, meaning the primary threat. They don’t meet our standards, but right now we have to deal with radical Islam and China.”

State Assembly races

Local voters also were asked to decide the winners of two state Assembly races Tuesday.

In the 74th District, which includes Costa Mesa, Laguna Beach, Newport Beach and part of Huntington Beach, incumbent Matthew Harper (R-Huntington Beach) was holding on to a slim lead over Laguna Beach Democrat Cottie Petrie-Norris, 50.3% to 49.7%, with all precincts reporting.

In the 72nd District, which includes Fountain Valley and a swath of Huntington Beach, Republican Tyler Diep was well ahead of Democrat Josh Lowenthal, 54.3% to 45.7%.

Lowenthal, of Huntington Beach, is a business executive and son of Rep. Alan Lowenthal (D-Long Beach). Diep is vice mayor of Westminster.

Diep’s campaign came under fire last week from some members of Orange County’s Jewish community who contended some of Diep’s mailers used anti-Semitic themes to attack his opponent, who is Jewish.

Diep’s campaign issued a statement denying allegations that it enlarged Lowenthal’s nose in a photo, saying, “Tyler is Vietnamese and fled communist persecution — he is highly sensitive to attempts at exploiting stereotypes to score political points.”

Bradley Zint is a contributor to Times Community News. Los Angeles Times staff writer Joe Mozingo contributed to this report.