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.

In Texas, the race gap appears more meaningful than the gender gap. Latino voters break sharply in O'Rourke's favor, 62% to 35%, while white voters favor Cruz by a 2-to-1 margin, 66% to 33%.

Likely voters in Texas place immigration at the top of their issue list: 26% call it the most important issue in deciding their vote, while 23% call the economy their top priority. Cruz leads among both sets of voters. O'Rourke has a wide edge among the 19% of voters who call health care their top issue. Eleven percent say their top issue is national security, 8% gun policy and 5% the investigation into Russian interference in the 2016 election.

Both Senate candidates hold net-positive favorability ratings with voters in Texas generally, and that holds among those most likely to vote. Cruz is viewed positively by 51% of Texas voters, 41% have an unfavorable view, and O'Rourke is seen favorably by 45%, with 36% holding a negative opinion. Cruz fares better among his own partisans (92% favorable among Texas Republicans) than O'Rourke does with Democrats in the state (81% favorable among Democrats).

The poll also finds Texas Gov. Greg Abbott standing well ahead of his Democratic challenger in the poll -- 57% of likely voters support Abbott with 39% for Lupe Valdez.

The CNN poll in Texas was conducted by SSRS October 9 through 13 among random statewide samples reached on landlines or cell phones by a live interviewer. Results for the full sample of 1,004 adults have a margin of sampling error of plus or minus 3.8 percentage points. For the subset of 862 registered voters, it is plus or minus 4.1, and for the 716 likely voters, plus or minus 4.5 percentage points.