Marine Johannes made five of seven from three-point range and finished with 15 points for the Liberty (19-6). Sabrina Ionescu added 14 points, six rebounds and five assists and Courtney Vandersloot scored eight points with nine assists and six rebounds.
New York, which played its seventh game in 12 days, is off to the best 25-game start in franchise history. The Liberty have won five of their last six.
Ionescu and Johannes each hit two three-pointers in a 19-0 run that made it 21-2 with 2:52 left in the first quarter. Nneka Ogwumike scored for the Sparks to make it 2-2 but they went scoreless for the next nearly-six minutes, missing 12 straight field-goal attempts.
Los Angeles (9-16), which had won back-to-back games over the Indiana Fever, has lost nine of its last 11.
Dearica Hamby scored 21 points, Jordin Canada added 17 and Azurá Stevens 13 for the Sparks. Ogwumike had 10 points.
The Liberty moved a game in front of third-place Connecticut in the WNBA standings, 3½ games back of first-place Las Vegas.
New York hit 15 three-pointers and finished with 26 assists on 32 made field goals. The Liberty became just the second team in WNBA history to have at least 12 games with 25-plus assists in a single-season, joining the 2022 Chicago Sky (18).