Lucario is a pretty skilled Pokemon and he won’t go down easily, but he’s up against a pretty powerful Digimon in this battle. Veemon has his Digievolutions and his power increases for each one. Once he’s in his Imperialdramon Fighter Mode form, the battle will be over for Lucario. Lucario just won’t be able to keep up with the insane amounts of power that Veemon can dish out. Veemon wins.
original art by BleedmanWorld
http://www.deviantart.com/art/Flamedramon-vs-Lucario-part-2-169647655
DReager1.com 
Honestly, it’s a close one. Yet, all Lucario would have to do is survive ExVeemon and Flamedramon and BOOM! Aura Sphere x50! Veemon wouldn’t last a second after getting tired out by that.
So, Lucario wins. It’s not strenght. It’s not speed. It’s instincts.
It is a close fight all right. With Lucario’s Mega Form, it could definitely go either way. If Lucario were to survive long enough to unleash his powerful attacks, then he could have a shot. His speed and power are about on par with Veemon, but Veemon’s final forms do have more attack power. I just gotta give Veemon the edge in this round