Can someone who knows about cars help me out?

ok, i just bought a 2007 Subaru wrx sti and me and my friends decided to race. my friend has Infiniti g35. i was so confident that i was going to beat him that i bet him $500. However, when we go to the freeway and started to race he beat me from start to finish. now, how is that possible? did i mess up on shifting gear or what because Subaru’s don't usually get beaten that easy, especially on the start!!!!