Not so much the power (that was mainly downhill) but the speed. I'd done that segment 35 times before and the closest I'd come was one second slower than the KOM. I was hoping to maybe pip it by a second but ended up 12 seconds faster.
Just one of those situations with the right legs, the right gentle tailwind and enough momentum over the top made a bigger difference than I expected.
I can do 606W for a minute. But don't particularly want to again.