@all of you saying Deidara wins, you're making it sound like Deidara c4 blitzes and the fight ends there.
If that was true he would have solo'd Hebi Sasuke low difficulty (don't give the plot bs because all it does is show you can't make an argument worth jack). C4 is something called a last resort technique.
Notice how it wasn't until Deidara got both arms sliced and thrown off the c2 dragon that he pulled it out? If you refer to my post on page 1 I gave a scenario where Kakuzu takes this. You guys underestimate Kakuzu so badly.
Let's not forget Kakuzu was fighting on part in Taijutsu with Part 2 Kakashi. Kakuzu is capable of closing the distance on Deidara if he's not in the air and using c1, Sasuke did it, Kakuzu is doing it. Especially since Kakuzu has chakra threads.
Deidara gets overwhelmed by 4 elemental attacks including lightning his weakness. Want me to make it worse? Heart and fire combine and overwhelm his c2 dragon even more. Want me to make it worse? Air heart can fly and trail his ass. Want me to make it worse? Deidara can't get c4 off unless he's out of range, if he suicides then the fight draws. I gave a scenario where if Kakuzu went for his heart it'd tie.