You can pull a Super Horn in First, but make sure it's in the second Item Slot, because Boo might steal it. Or, you can use Lakitu(timing must be clean and you need a high Invincibility), a stage hazard(Blue Shell drops your speed to zero, but stage hazards only cut speed a bit), or let someone pass(if the shell is far out, and the distance between you and Second Place is tight, meaning no frontrunning).