I believe there is a move you can do that suspends the opponent in the air for a short while and you can get right underneath them and perform the Level 1. I think the move is down circle. Could be wrong though.
Thanks for correcting me about the up circle move. But Ive had no problem connecting with it after pulling off the up circle move. You just need to move forward a bit prior to pulling off the Super. You need to be right under him. I'm sure they will fix this when it comes time to rebalancing out the characters.
Keep practicing you'll get the hang of it buddy.
Do you play LBP2? If so, could you take the time to check out my levels?
Check out my LBP.ME