Democrats easily kept control of a Texas House seat Tuesday night, holding off another push by the state's top Republicans to flip a solidly blue district in a special election runoff.

With all precincts reporting, Democrat Ray Lopez defeated Republican Fred Rangel, 58 percent to 42 percent, according to unofficial returns. Rangel called Lopez to concede minutes after the final results came in.

Lopez, a former member of the San Antonio City Council, is now set to replace former state Rep. Justin Rodriguez, D-San Antonio. Rodriguez gave up the seat in January to become a Bexar County commissioner.

Rangel, a longtime GOP activist, had the support of high-ranking Texas Republicans, including Gov. Greg Abbott and U.S. Sen. John Cornyn. They had hoped to replicate the success they had last year in Senate District 19, where they captured a seat under similar circumstances.

But Democrats were determined to prevent another humiliating upset, and they presented a more organized, united front once Lopez advanced to the runoff. In congratulating Lopez on Tuesday night, the Texas Democratic Party noted it invested over $15,000 to help Lopez with things like digital ads and a vote-by-mail program.

"The Texas Democratic Party leveraged our voter engagement programs to make sure Ray Lopez won tonight and to build our Party infrastructure for 2020," state party chairman Gilberto Hinojosa said in a statement.

Republicans, meanwhile, expressed some optimism in defeat. Texas GOP Chairman James Dickey claimed in a statement that Rangel "forced Democrats to feverishly work to keep their hold in this longtime blue district and awakened more Republicans to vote in this special election."

Rangel finished first in the initial Feb. 12 contest, getting 38 percent of the vote to 20 percent for Lopez. Rangel was the only GOP candidate in the race, while Lopez faced three fellow Democrats. They backed him in the runoff, as did every Democratic member of the Bexar County delegation to Austin.

Lopez celebrated the win at his election night party with Democratic presidential candidate Julián Castro, the former San Antonio mayor and U.S. housing secretary. Castro's twin brother, U.S. Rep. Joaquin Castro of San Antonio, represented HD-125 from 2003-13.

The HD-125 runoff was the final contest since the November midterms to fill a vacant seat in the Legislature. After Lopez and state Rep.-elect Christina Morales, D-Houston, take office in the coming days, all 150 House seats will be occupied again, with 83 Republicans and 67 Democrats.