I did that in the Practice room. In the actual race, I believe my best was a 1:57.1. I believe a 1:56 is possible. From what I saw, the practice room gives you absolutely perfect traction the entire time. Online, I believe you get that only one lap or so, so it's hit or miss if you can achieve that same lap time. For me, lap 4 or 5 seemed to give me the same grip that I had in the practice room. So while I could do lap after lap in practice to get it right, online you had to nail it when the tires were perfectly warmed up and not very worn.
MX