Rep. Brad Sherman (D-Calif.) defeated fellow Democratic Rep. Howard Berman in their member-vs.-member match-up.
It was a nasty campaign, with the two lawmakers almost coming to blows during a debate and having to be separated by a police officer.
The redistricting process put the two men in the same seat, which contained much of Sherman's old territory. Under California's new primary system, the top two vote-getters, regardless of party, move on to the general election.
Democratic leadership indicated a preference for Berman, with Rep. Steny Hoyer (D-Md.), the No. 2 in leadership, endorsing him. Berman also had the endorsement of prominent Republicans like Sens. John McCainJohn McCainSenate rivals gear up for debates McCain opponent releases new ad hitting his record Why is the election so close? Experts say it's all in your head MORE (R-Ariz.) and Lindsey GrahamLindsey GrahamOvernight Finance: McConnell offers 'clean' funding bill | Dems pan proposal | Flint aid, internet measure not included | More heat for Wells Fargo | New concerns on investor visas Senators buck spending bill over Export-Import Bank Pelosi pans latest GOP stopgap spending offer MORE (R-S.C.), who cited his work on the House Foreign Affairs Committee.
Sherman, meanwhile, had the support of former President Clinton.
—This story was updated at 5:28 a.m.