Gaara sand caught deidera with his sand and his speed is 4.5, i think kakashi has either that or a 4, so he's not faster then gaara sand
I'm not sure about Deidaras feats, but Kakashi has 4.5 in speed. Also Deidara got caught only because he underestimated Gaara and broke his guard and it's not the first time that that happened. Even against Naruto, Kakashi said that:
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Deidara had the false habit to be too much confident that he break sometimes his guard without knowing. It also happened against Sasuke. That's not about speed, but just being able to be careful. And Kakashi is always calm and careful when he fight, and also don't forget the Sharingan that helps him to see something happen before it even happens. That helps a lot to anticipate actions.
Anyway i see Kakashi winning because he has more experience(i think they are almost equal in intelligence or maybe Kakashi is a little bit more intelligent), he is fast, use clone really wisely and he has a huge array of technics like Suiton jutsu which could be really dangerous for Gaara, doton technics to protect himself, raiton technics like Raikiri or lightning chain which could break thru Gaaras defense easily, etc