John Curtis won Tuesday night's primary challenge in Utah, taking one step closer to potentially replacing retiring moderate Republican Sen. Mitt Romney.

Curtis was leading with 52% of the vote when the Associated Press called the race.

He will now proceed to the November general election and face Democratic nominee Caroline Gleich. Utah hasn't elected a Democrat to the U.S. Senate since 1970. 

UTAH GOP CHOOSE TRUMP-BACKED CANDIDATE AS NOMINEE TO REPLACE SEN. ROMNEY, BUT PRIMARY STILL TO COME

Runner-up candidate Trent Staggs was at 28.2%. Staggs built his base by calling delegates personally and courting the endorsements of Trump and many of his allies nationwide. The former president wrote on his Truth Social platform in April that Staggs is a "100% MAGA" candidate who knows how to stop inflation, grow the economy and secure the U.S.-Mexico border. 

UTAH GOP CHOOSES TRUMP-BACKED CANDIDATE AS NOMINEE TO REPLACE SEN. ROMNEY, BUT PRIMARY STILL TO COME

Staggs was the first candidate to enter the Senate race, even before Romney announced he was not seeking reelection.

Rep. John Curtis, R-Utah, is currently the longest serving congressman in Utah's House delegation and positioned himself as an alternative to the Trump-endorsed Staggs. A former mayor of the city of Provo, Curtis, 63, has served in Congress since 2017, winning a special election that year and reelection by wide margins ever since.

CLICK HERE TO GET THE FOX NEWS APP

Like Romney, Curtis hasn't endorsed Trump for president, likely squaring him with Romney's base, and leans more left on issues like climate change compared to the rest of the Republican flank. 

Another conservative candidate, former state House Speaker Brad Wilson, despite loaning $3 million to his campaign, lost at the April state Republican convention to Staggs and was once considered a leading contender. Meanwhile, candidate Jason Walton positioned himself as a businessman similar to Trump.

The Associated Press contributed to this report.