Washington (CNN) Texas Republican Sen. Ted Cruz appears well-positioned for re-election over his Democratic challenger Rep. Beto O'Rourke, topping him 52% to 45% among likely voters, a new CNN poll conducted by SSRS finds.

Just 9% of likely Texas voters say there's a chance they could change their mind about the Senate contest before Election Day, although O'Rourke's voters are more apt to be locked in to their choice (92% say their minds are made up) than are Cruz's backers (87% say they've made a final decision).

The two candidates are set to debate Tuesday night, and O'Rourke will participate in a CNN town hall later this week. O'Rourke's challenge has drawn tens of millions in donations, forcing Republicans to play defense in one of the few Republican Senate seats in play this election cycle. President Donald Trump even plans to host a rally for his former rival's benefit.

The President could be an asset among those planning to vote in Texas. Trump's approval rating is net negative statewide, with 50% of adults disapproving of his handling of the presidency vs. 41% who approve. Among likely voters, however, 49% approve of Trump's job performance and 48% disapprove.

The gender gap in this race is tighter than what CNN has measured in nationwide polling on the House generic ballot and in other Senate contests. In four other critical battlegrounds, the gender gap has been 30 points or higher in three states, and stood at 21 in the fourth. In this contest, it's a narrower 18 points. O'Rourke holds just a 2-point edge among women, the smallest for a Democrat among women in the states CNN has polled so far. The next closest is Jacky Rosen's 14-point lead among women in Nevada earlier this month in her race against Republican Sen. Dean Heller.

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