Three-term mayor Gregg Hull wins the three-way GOP primary and will take on the former Interior Secretary in November.
Votes to determine the runner up, who will advance alongside incumbent Mayor Karen Bass to the general election, are still coming in.
Lahn, a self-described farmer and businessman, defeated Rep. Randy Feenstra for the Republican gubernatorial nomination, defying expectations.
Cook Political Report has shifted the race from ‘Solid R’ to ‘Likely R.’

The Republican congresswoman will face Christina Bohannan in November in the swing-prone Iowa district.
Candidates are seeking a U.S. Senate seat currently held by Republican Sen. Joni Ernst, who decided not to seek reelection.
The ‘Familiar Faces’ feature was designed to alert homeowners about who is approaching their front door, the company said.
An open letter says many UC Berkeley students aren’t prepared for calculus, while some University of San Diego students can’t even do middle school math.
The attack came ahead of the 37th anniversary of the Tiananmen Square massacre, as overseas memorials preserve a history censored in China.
A glimpse into the world through the lens of photography.

Critics have called on Congress to make the government review process mandatory instead of voluntary.
President Donald Trump says the new event will be held at the Waldorf Astoria.
National Intelligence Director Tulsi Gabbard is stepping down on June 30.
Supporters say it can rein in local government spending, but critics warn it will hamstring Florida’s cities.
NOAA forecasts eight to 14 named storms in the Atlantic Ocean this season, and looks to drones and AI to improve prediction accuracy.
People who may see suspicious activity involving ballots or election matters are advised to report it to the LA County Clerk and Registrar’s Office.
The update is applicable to a Coast Guard program that only accepted students from minority-serving institutions.
Civil rights organizations file a federal lawsuit accusing ICE of abusing detainees at Camp East Montana in El Paso, Texas.
New Jersey Governor Mikie Sherrill said out-of-state protesters are creating problems at an ICE detention facility.
Trump has been steadily raising pressure on Havana in recent months and has hinted at a military action against the communist-led state.
ICE officers are facing an 8,000 percent increase in death threats, DHS Secretary Markwayne Mullin said.
Carriers are increasingly competing on product rather than price, aviation industry insider William Swelbar said.