The Blues, who have won the Community Shield and Continental Cup and beat Bayern Munich to qualify for the Champions League final on Sunday, are on 54 points, two ahead of Manchester City with a goal difference of 54 compared to City's 51.
Australian Kerr put Chelsea ahead in the 41st minute when Norwegian winger Guro Reiten volleyed in a brilliant cross and although Bethany England failed to connect, Kerr was on hand to slam the ball into the net.
Reiten picked out Kerr again seven minutes into the second half. Her initial header was parried by Spurs keeper Rebecca Spencer but Kerr blasted home the rebound for her 20th goal of the season.
Opinion: Havertz can take league by storm after debut season filled with challenges
Chelsea host sixth-placed Reading on Sunday and Manchester City visit West Ham United, who are ninth in the 12-team league and safe from relegation.
Andriy Shevchenko leaves his role as head coach of Ukraine
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