Matildas captain Kerr was at her deadly best to score both goals of the Spurs victory which puts them on the brink of winning the league title - two points ahead of Manchester City with one game remaining.
Hayes discussed getting the best out of the Aussie star in a team packed with international talent.
"[Kerr] is a delight, she really is," said Hayes in a press conference.
"I’ve figured out the strategies that work best with her and when it’s your season, things go for you in the same way as it did for Beth (England) [Chelsea's top scorer last season] last year.
“The ball is falling to her, she’s taking responsibility for the team which I think is important and she does it again and again.
“I feel a bit bad not leaving her on to get her hat-trick but we’ve got other games to prepare for and I didn’t want to take any risks.”
Those risks refer to potential injury to star players, with two season-defining matches looming.
Chelsea’s WSL title-decider is against sixth-placed Reading at 11:30pm AEDT this Sunday.
Kerr and co. will play the UEFA Women's Champions League final at 5:00am AEDT Monday 17 May against a mighty Barcelona side who are undefeated in the Spanish league this season.
