HOUSTON — U.S. Sen. Ted Cruz, R-Texas, won a narrow victory Tuesday over U.S. Rep. Beto O’Rourke in the most expensive Senate race in U.S. history.

With nearly all the vote counted early Wednesday, Cruz held a 3-percentage point lead over O’Rourke, and the Associated Press had called the race for Cruz.

Cruz’s hard-won victory was closer than Democrats had any right to dream when O’Rourke, a little-known three-term congressman from El Paso, first set his sights on defeating Cruz, who in his first term in office ran a strong race for the Republican presidential nomination that, but for Donald , he might have won.

O’Rourke rolled up big margins in Travis, Harris, Dallas and Bexar counties and in the reliably Democratic border counties. He also expanded the electoral map for Democrats, winning Williamson and Hays counties, giving a boost to four Democratic Texas House candidates who defeated Republicans in GOP-held districts on the fringes of Austin.