Republicans maintained control of the Senate Tuesday as Sen. Ted Cruz won reelection against Democratic challenger Beto O'Rourke in one of the most closely watched races in the country, NBC News projects.

Cruz held off a strong challenge from O'Rourke, the 45-year-old congressman from El Paso. O'Rourke's unique campaign style and wildly successful fundraising — he raised more than $70 million in his bid for Senate — made the race highly watched, even as the Democrat trailed in the polls.

Democrats have not won a statewide election in Texas since 1994.

With 79 percent of the vote tallied, Cruz was leading O'Rourke 51 percent to 48.4 percent.