Who was Spike's syre??

I'm watching the episode where Spike first comes to Sunnydale.
And Angel just tried to trick him into thinking Angelus was back and then Spike yells, "You were my syre man!"

But I thought Dursilla was his syer because in other episodes of flashbacks, Dru is the one who follows him, offers him eternal life and bites him. So isn't she his syre then??