Juggernaut vs. Shatterstar
I'll wager that Shatterstar's combo sword can destroy Juggernaut's magic shield; with his first mutant strike. That's the most powerful one.
Then all he'd Have to do is fight him for like half an hour till his power reamps cause i doubt a lesser strike would kill Juggernaut.
Everyone knows how his power works.
First strike and it's over. 2nd still real powerful and third sort of rank.