Los Angeles scored seven of the final nine points to secure its first victory since beating Dallas in back-to-back games in late June.
Ogwumike grabbed a loose ball in the paint and scored to pull Los Angeles within 78-76 with 38.1 seconds left. Indiana worked down the clock, but Victoria Vivians was off on a long three-pointer at the end of the shot clock.
After Canada sank a contested three-pointer, Indiana’s Kelsey Mitchell had a good look from the top of the three-point arc but it didn’t hit the rim.
Canada finished with 20 points and 10 assists for Los Angeles (8-15). Azurá Stevens added 15 points.
Canada scored 11 of her 13 first-half points in the second quarter to help Los Angeles build a 47-38 lead. Ogwumike added 15 points in the first half and Stevens had 11 as the Sparks shot 56% from the field.
Mitchell scored 14 of her 19 points in the second half and Vivians added 17 points for Indiana (6-17). Erica Wheeler had 15 points and eight assists. Aliyah Boston battled foul trouble and finished with nine points in 26 minutes.
The two teams play each other again on Thursday at Crypto.com Arena.