Best fighter in the group?

[joking.livejournal.com]

I was randomly wondering today – who among the Animorphs would you say is the best fighter? I don't mean in terms of tactics and strategy, just raw kickassery. 

I would say it's either Rachel or Ax, but I can't decide which. But you may disagree with me. You could even make a case for David being the best fighter, since none of the Animorphs were able to defeat him in single combat.