Luffy vs Rob Lucci
That fight had high stakes. The SH fighting an hopeless battle against multiple Warships while waiting for their captain.
Ussop having a emotional moment with Luffy. Luffy defeated Lucci by pure willpower. No flashback PU, no haki PU, no OP devil fruit. Just a pure fist fight.
Zoro vs Mr. 1 is close second
Zoro fighting desparately to overcome his opponents iron defence. Daz bones ruthlessly slices and dices Zoro up. No flashed out fight. And one of the most badass finishes to a fight.