By Steve Contorno, CNN

(CNN) — Illinois Lt. Gov. Juliana Stratton has won the Democratic primary for an open Senate seat, a stunning rise for a little-known state officer now on a glide path to Washington.

If victorious in November, Stratton would become the second Black woman to represent Illinois in the Senate – and just the sixth Black woman senator in US history. Former Illinois Sen. Carol Moseley Braun in 1992 became the first Black woman ever elected to the Senate.

She would join Sens. Lisa Blunt Rochester of Delaware and Angela Alsobrooks of Maryland in giving the Senate three Black women members for the first time.

Stratton’s victory was engineered in part by JB Pritzker, Illinois’ billionaire governor and her former running mate. Pritzker backed her early in the race and donated $5 million to a pro-Stratton super PAC largely run by his close political operatives.

Stratton leaned heavily on Pritzker’s popularity with Illinois Democrats. He appeared regularly in ads and campaign literature supporting her, and she often touted his support and their work together on the campaign trail.

It’s a crucial demonstration of Pritzker’s political prowess in his backyard as he considers a bid for president.

Stratton will now face GOP candidate Don Tracy, a former Illinois Republican Party chair, in November.

Stratton beat a crowded field that included two members of the Illinois congressional delegation: US Reps. Raja Krishnamoorthi and Robin Kelly. Krishnamoorthi in particular mounted a spirited campaign, bringing in $30 million through late February, which allowed for a sustained television ad push that began last summer while his opponents were still scrambling to raise money to get on air.

Tuesday’s race attracted far less national attention than the hotly contested Democratic primary for a Texas Senate seat earlier this month. But the winner here is substantially more likely to join the US Senate with an opportunity to remain there for decades. Illinois is a deep blue state, and the office’s current occupant, 81-year-old Sen. Dick Durbin, was first elected in 1996.

While many in Illinois – including the campaigns of his rivals – saw Krishnamoorthi as the front-runner entering the final stretch, they were also encouraged that his vast financial advantage had failed to grow his support, sources told CNN, creating an opening for a late surge.

Her victory defied some strategists’ belief that two prominent Black women in the race could split the African American vote and make it difficult for one to win.

Even Stratton’s supporters expressed fear that Kelly, who was backed by the Congressional Black Caucus, would cut into her base. New York Rep. Yvette Clarke, who leads the influential caucus, accused Pritzker before Tuesday’s election of an “effort to tip the scales” in the contest. They were further exposed when pro-Krishnamoorthi forces spent the final days of the campaign trying to boost Kelly, presumably expecting her to carve into Stratton’s support.

“She has a proven record of doing what she thinks is right and not tying herself to anybody else. She’s always been an independent voice,” said Jade Brown, who told CNN she struggled with whom to vote for in the Senate race but ultimately decided on Stratton as she cast her ballot in a downtown Chicago polling location.

On the campaign trail, Stratton said she would push to abolish US Immigration and Customs Enforcement, the federal agency charged with carrying out President Donald Trump’s immigration crackdown. She also supported a $25 per hour minimum wage and expanding Medicare access to all Americans.

Her campaign had support from influential figures like Massachusetts Sen. Elizabeth Warren, who joined her on the trail during the final weekend, and Illinois Sen. Tammy Duckworth, as well as several of the state’s powerful unions, including the Illinois Federation of Teachers.

Stratton, born and raised on Chicago’s South Side, was a lawyer before winning a state House seat in 2016. Pritzker tapped her to join him on the Democratic ticket in 2018, and she has served as his lieutenant governor for the past eight years.

This story and headline have been updated with additional details.

The-CNN-Wire