OSHKOSH, Wisconsin — Donald Trump is planning to make his first campaign visit to Wisconsin on Tuesday, where the upcoming Republican presidential primary could mark a turning point in the unpredictable GOP race.

But rival Ted Cruz has gotten a jumpstart on the contest, racking up influential endorsements, campaigning in key regions and supported by bullish advertising campaign.

A solid Cruz win in Wisconsin would narrow Trump’s path to the nomination, heap pressure on the billionaire to sweep the remaining winner-take-all primaries this spring, and increase the chances of a contested party convention in July.

“The results in Wisconsin will impact significantly the primaries to come,” Cruz told The Associated Press after a rally in Oshkosh Friday. “Wisconsin, I believe, will play a critical role continuing to unify Republicans behind our campaign. The only way to beat Donald Trump is with unity.”

Cruz is positioning himself to win Wisconsin, next Tuesday’s only contest, and the first primary since he began collecting the backing of establishment Republicans, such as former Florida Gov. Jeb Bush, adamant about eliminating Trump.