EXCLUSIVE: A top Senate Republican is heading across the country this month to hit the campaign trail with conservative firebrand Kari Lake in Arizona, a state seen by many in the GOP as crucial to the party winning a majority in Congress' upper chamber, as well as the White House, in November.

Sen. John Barrasso, R-Wyo., who serves as chair of the Senate Republican conference, will join Lake in Phoenix on Feb. 29 for a number of campaign stops that will focus on the border crisis and the economic issues they say are plaguing Americans under the Biden administration.

"Kari Lake has put Arizona on the map for a Republican takeover in November. Kari Lake will bring Arizona hard work and no-nonsense to the U.S. Senate. I’m excited to campaign with her in Arizona," Barrasso told Fox News Digital on Wednesday.

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Republican Arizona Senate candidate Kari Lake

Kari Lake, Republican Senate candidate for Arizona, during a television interview at a New Hampshire primary election night watch party with former President Donald Trump, not pictured, in Nashua, New Hampshire, on Tuesday, Jan. 23, 2024.  (Al Drago/Bloomberg via Getty Images)

Barrasso was the first major congressional leader to endorse Lake, who ran unsuccessfully for Arizona governor in 2022, in the days following her campaign launch last October.

The move was followed by a number of other big names that view the former news anchor as the best chance for Republicans to flip the seat currently held by independent Sen. Kyrsten Sinema. Those names include former President Donald Trump, Sens. Tommy Tuberville, R-Ala., Roger Marshall, R-Kan., Tom Cotton, R-Ark., and Reps. Jim Banks, R-Ind., and Burgess Owens, R-Utah.

"I am so thankful for Senator Barrasso’s endorsement, advice, and support. He is a conservative warrior in the Senate. The Senate Majority will run through Arizona, and having Senator Barrasso on the campaign trail shows just how important this race will be for the future of our country," Lake told Fox News Digital.

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Republican Wyoming Sen. John Barrasso

Senator John Barrasso (R-WY) holds up a front page from The New York Post as he speaks during a press conference following the Senate Republican weekly policy luncheon at the U.S. Capitol on January 9, 2024 in Washington, DC. (Samuel Corum/Getty Images)

Arizona is expected to be one of the most closely watched races in 2024, and is widely seen as one of the best flip opportunities for Republicans, alongside West Virginia, Ohio, Montana and Nevada. Democrats currently hold a 51-49 majority with the support of Sinema and her fellow independent Sens. Bernie Sanders, I-Vt., and Angus King, I-Maine.

In recent cycles, races in the state have been decided within tight margins, including in 2022 when incumbent Democrat Sen. Mark Kelly defeated Republican businessman Blake Masters by less than 5%, a 2020 special election when Kelly defeated appointed Republican Sen. Martha McSally by less than 3%, and in 2018 when Sinema defeated McSally by just over 2%.

This time, though, Republicans say Lake is a stronger candidate than her predecessors, and that the outlook of her race is already better than those in some of the other states holding elections this year.

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Republican Arizona Senate candidate Kari Lake

Kari Lake arrives at the caucus night party hosted by Republican presidential candidate former President Donald Trump at the Iowa Events Center on January 15, 2024 in Des Moines, Iowa. (Alex Wong/Getty Images)

"Kari Lake is the presumptive Republican nominee and is running a really strong race in Arizona. Her fundraising numbers are very competitive, and she is polling better than other GOP challengers in Montana, Pennsylvania, Michigan, and Wisconsin. She is in a strong position to flip this seat red," one Republican strategist told Fox News Digital.

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Lake's only major opponent in the Republican primary is Pinal County Sheriff Mark Lamb, and, should she become the nominee, will likely face Phoenix-area Democrat Rep. Ruben Gallego in the general election.

Early polling of a hypothetical matchup between Lake and Gallego suggests a tight race, even when including Sinema, who has not yet said whether she will run for re-election after announcing her departure from the Democrat Party in Dec. 2022.

Get the latest updates from the 2024 campaign trail, exclusive interviews and more at our Fox News Digital election hub.