Connecticut (7-1) is off to its best start since winning eight of its first nine games in 2008.
Camille Little added 14 points for Connecticut. The Sun scored the first six points of overtime and Los Angeles didn't hit its first field goal until the 5.3-second mark.
Jantel Lavender had 22 points and 12 rebounds for Los Angeles (0-6). Andrea Hoover, a rookie from Dayton, made her first WNBA start for Los Angeles and had season-high 17 points in 40 minutes. Nneka Ogwumike, in her second game back after an ankle injury, scored 14 points.
Los Angeles went three-plus minutes without a field goal in the fourth quarter, but Jennifer Lacy's 3-pointer from the corner pulled the Sparks within 66-65 with 57 seconds left. Connecticut's Alyssa Thomas went 1 for 2 from the line for a two-point lead and Jantel Lavender's layup tied it at 67 with 9.9 seconds left.
In the first half, Connecticut was down by as many as 14 points but scored the final eight points of the half, including the Sun's first 3-pointer, to cut its deficit to 32-26. Shekinna Stricklen's 3-pointer with 2:29 left in the third quarter gave Connecticut its first lead since it was 4-2.
Los Angeles was without two-time league MVP Candace Parker, Kristi Toliver and Alana Beard. Toliver is expected to return soon.