The first 20 games you play can show some wild rating swings. There is no error in your graph. See here: FAQ
Originally posted by WcoasterYour opponent was rated at 1328 while your were rated at 1200.
Thanks for the info. Still can't see how that formula would generate a variance like that. Maybe we were both P at the time.
From the FAQ Each game is scored as being your opponent's rating plus 400 (for a win).
As such you jump to 1728.
It could have been worse, you could have beaten some rated at 2,100 and jumped to a rating of 2,500!!