Kelsey Plum sank a pull-up jumper from the free-throw line with 15.8 seconds left to give Las Vegas a 92-88 lead. Tiffany Hayes was off on a long 3-pointer at the other end and Kayla McBride sealed it at the line.
McBride scored 21 points, with five 3-pointers, for Las Vegas (17-9). Jackie Young chipped in with 17 points and Plum was the lone Aces starter not in double figures with nine.
Atlanta (5-20) has lost 10 straight games, its longest streak since a 4-30 season in 2010.
Jessica Breland scored 18 points and Marie Gulich had her first career double-double with 15 points and 12 rebounds for Atlanta. Hayes was just 2 of 12 from the field for 10 points after setting a career high with 34 on Saturday at Indiana.