I know my man...Trust me i know , But he has the speed feats. Outrunning Gaara's sand which is much more agile and could even match speeds with Sasori's In a desert none the less is a speed feat on its own, then he has outrunning team gai without arms ... His speed is fine, Not to mention he would most likely be up in the air for the fight
We're talking about the location mentioned in the OP are we not? In which case outrunning and flying are a bit tough at first. Plus, you are assuming Sasori would even allow Deidara to take flight. Remember that Sasori knows a lot about Deidara and out of the 2 of the, Sasori always felt like he was superior. There's a manga page just before the Sasori fight where he says that he is stronger than Deidara. But leaving that aside, outrunning someone and fighting against someone are two different things. Deidara can probably run away from this fight, but to win, he'll have to face off against 100+ puppets. Not to mention the strongest Kazekage (leave Gaara out of this for now).
It won't be an easy match-up, but Sasori wins against Deidara. Also if you consider their state of mind IC, then Sasori definitely wins it. Deidara messes around too much and gets too overconfident, while Sasori doesn't play around.
