Updated at 11:40 a.m. on Wednesday: Revised to include comment from the Cuellar campaign and Jessica Cisneros.

WASHINGTON – Laredo Rep. Henry Cuellar, one of the most conservative Democrats in Congress, fended off a serious primary challenge from Jessica Cisneros, a 26-year-old immigration lawyer who brought the full force of the progressive left to South Texas.

Cuellar, an eight-term incumbent, secured a narrow victory early Wednesday in one of most closely watched races across Texas, if not the country.

That high profile was saying something, too, given the unusually competitive primary season that formed in the Lone Star State after six Republican congressmen decided to call it quits and Democrats targeted pickup opportunities in a number of other shifting districts.

While much of that attention centered on North Texas, the state’s primary map was chock full of intriguing matchups.

In South Texas, Cisneros came out of nowhere to put Cuellar on the defensive. She tagged him as an out-of-touch faux-Democrat, while earning endorsements from progressive all-stars like Massachusetts Sen. Elizabeth Warren and New York Rep. Alexandria Oscasio-Cortez.

Cuellar — backed by both House Speaker Nancy Pelosi and groups funded by the Kochs, a family of GOP mega-donors — countered that Cisneros was an uninformed interloper who didn’t understand the centrist sensibilities of a border district that stretches from McAllen to San Antonio.

Cisneros said on Wednesday that “this is just the beginning.”

“The first thing we had to defeat was the culture of fear -- and our movement was victorious in proving we’re within striking distance of bringing fundamental change to South Texas,” she said.

Cuellar spokesman Colin Strother said the race ended up being “closer than expected,” though he noted that Cuellar once won a race by just 58 votes.

“We hope this sends a message that we’re still a big tent party and that moderate and conservative voices are still welcome,” he said, adding that Cuellar was “obviously pleased” with the result. “It’s key to us maintaining and growing our majority.”

With Bexar and Zapata now 100% reporting, we are calling #TX28 for @RepCuellar @CuellarCampaign . Thank you to all of our supporters. pic.twitter.com/oMzLyWFyQ4 — Colin Strother (@ColinStrother) March 4, 2020

The intense intra-party clash mirrored the battle in North Texas between Rep. Kay Granger, a longtime Fort Worth Republican, and her aggressive primary competitor, former Colleyville City Council member Chris Putnam.

Granger, like Cuellar, serves on the powerful House Appropriations panel. Granger, like Cuellar, was attacked by their party’s edge, the left in his case and the right in hers. Granger, like Cuellar, received robust support from party leaders to produce a gusher of spending on all sides.

Granger secured a victory late Tuesday. Cuellar did the same a few hours later.

Many other major primary battles in Texas appeared to be heading to runoffs, reflecting the inordinate interest in some of the state’s congressional seats. The competition will likely heat up as the November general election approaches.

Here’s a look at a few other results of note:

District 17

Former Dallas Rep. Pete Sessions’ comeback bid remains alive.

The Republican – who was upset last cycle by now-Rep. Colin Allred, D-Dallas – sought to try his luck in the Central Texas GOP stronghold that’s being vacated by Rep. Bill Flores, a Bryan Republican who decided to not run for reelection.

Sessions – who grew up in Waco, the district’s largest city – advanced to a runoff. Renee Swann, a Waco businesswoman endorsed by Flores, was battling with George Hindman, a retired NASA engineer, for the second runoff slot.

Going forward, the ex-congressman will have to bat away attacks that he’s a carpetbagger who moved to the district just to run for office. He’s also emerged as a peripheral figure in Trump’s Ukraine saga, though he’s not been accused of criminal wrongdoing.

District 13

A Trump Tweet is a powerful thing.

Ronny Jackson, the former White House physician, was positioned late Tuesday to make the runoff in a crowded GOP primary to replace retiring Clarendon Rep. Mac Thornberry, the top Republican on the House Armed Services Committee.

Jackson was boosted by a late Twitter endorsement from the president, who briefly picked the doctor and retired Navy rear admiral to serve as Veterans Affairs secretary before allegations came out about potential professional misconduct by Jackson.

So despite having only tenuous ties to the sweeping Panhandle district, Jackson was poised to face off in the next round against Josh Winegarner, a lobbyist who was endorsed by Thornberry and key figures in the cattle ranching industry.

District 22

So much for the next name in Texas’ most notable political dynasty.

Pierce Bush, grandson of former President George H.W. Bush, did not make the runoff from the jumbled GOP primary to replace Rep. Pete Olson, a retiring Sugar Land Republican who last cycle faced a closer-than-expected fight in the general election.

Bush, whose uncle is former President George W. Bush, was battling for third late Tuesday. Instead, Fort Bend County Sheriff Troy Nehls and and self-funded GOP activist Kathaleen Wall advanced to the runoff.

The eventual Republican nominee will square off in November against Sri Preston Kulkarni, the Democrat who last cycle gave Olson a real scare. That result caused Democrats to circle the suburban district outside of Houston as a priority in the 2020 campaign.