Sonic has been known to move so fast that he can make many afterimages of himself at will. If you can make many afterimages of yourself then you’re moving very, very, very damn fast. And he wasn’t even using Chaos Control!
 
It’s all true and has been proven as a fact in Archie Sonic the hedgehog issue #50 when Sonic used the afterimage move to fool Eggman’s hedgehog tracking missiles.
 
And seeing as Fili-second can’t make afterimages of herself. She is slower than the blue hedgehog.
 
Sorry Fili, but Sonic wins.

Assuming Sonic doesn’t bring in the Chaos Emeralds, Pinkie Pie/Fili-second wins due to her randomness.

Sonic will win

Sonic is better and fast then Fili second

@Background Pony #5A9F  
What matchup? The one in the image? I wasn’t even remarking on that. I was remarking on the flawed and incorrent stats used in Death Battle. Nothing ‘renegade’ about it. Really, I’m not sure what you’re trying to discredit here.

@Background Pony #CC28  
I noticed this is him using M-Speed in this one, allowing him to skip a whole section.

Since OP never specified which version of Sonic we’re going with, I’m forced to assume AoSth Sonic, who is the bastard lovechild of Sonic and Bugs Bunny, is allowed. He’s been exploiting toonforce since Faust was still in college. And like Bugs Bunny, AoStH Sonic always uses trickery and misdirection to outwit his foes, something Pinkie has never done(or if she has, she never does so frequently). I’d say in that case Sonic > Fili-Second.  
Also, Pinkie never seems to be able to exploit toonforce in serious situations. She was pretty useless on her own against Discord, the Hydra, Sombra, and many other serious villains.  
@Agent Tasmania  
Speed is pretty important in any “who would win?” scenario. Ever heard of a speed blitz? A character who can move many times faster than the other character can think is going to win 100% of the time, which frankly is why Superman would curbstomp Batman every single time if Supes ever got serious. That is also why any version of Sonic would easily defeat Fili-Second, as they’ve all had much more impressive showings of speed.  
@Agent Tasmania  
Hey, I think Spider-Man is a better character than Superman, but I have to acknowledge the latter would effortlessly defeat the latter in a serious fight.

Everyone’s focusing on the speed, As if this where a race.

@Background Pony #CC28  
I like how you ignore the actual matchup, you renegade you.

@Master Fox  
Death Battle’s data on Sonic’s speed is horrendously, and hilariously, underpowered. Just like their data on Rainbow Dash’s speed is hilariously OVERpowered.
 
Sonic CASUALLY achieves Mach 1 the same way that you and I skip from the couch to the fridge in the kitchen. The way you and I might jog to the store down the street and then back again? That’s Mach 5. Actually sprinting as hard as he can? Mach 10+.
 
The dude outran a freaking singularity for thirty seconds.
 
Rainbow Dash, in the meantime, got listed as being Mach 5+ by Death Battle. Which is wrong, wrong, wrong all over. She’s Mach 0.8~1.8 at the most when using Sonic Rainboom. Without Sonic Rainboom she isn’t even THAT fast.

@AetherKnite7z  
That’s not even KAKIPI’s best speed on that stage. Try this on for size: v=TVIAyaGa0MM

Guys, can Pinkie beat this?  
http://www.youtube.com/watch?v=Glfx6LBbbGY

We have the fastest pony in mare-tropolis vs the fastest thing alive

@Agent Tasmania  
Yay! The first time I’ve been actually corrected on the internet about math! Congrats. Btw. I used google to do my conversions from miles to meters.

@Master Fox  
That maths is appalling.  
765x1610 (miles into meters) = 1,231,650 meters per hour  
‘/. 360 (hours into seconds) = 3,421.25 meters per second.  
You performed the first operation wrong and didn’t perform the second at all.  
So Filisecond is roughly 4 times faster than cruising Sonic.

Result: Sonic and Fili-Second would question why they’re fighting and run off and do something else.

Again guys, it doesn’t matter how fast Sonic is, Pinkie can be there first just by nature of her character.  
And that’s just base Pinkie.

Lets see… pinkie pie had 1/2 a second to move from her spot to a bakery 64 blocks away and back. so a total distance moved would be 128 blocks. There’s no average block size so I’m going to just assume 100 meters per block, the average block size in the city of Houston. Not counting roads, that would be 25,600 meters per second.
 
Sonic’s top speed has yet to be calculated, but Screw Attack’s Death Battle has stated he’s got a cruising speed of 765 miles per hour OR 4,431,600 Meters per second.
 
SO!!! Folks, as much as I’d love to say Pinkie Pie wins. Sonic is 173 times faster then Fili-Second’s highest known speed.
 
The only way for Fili-Second to win is to use Sonic’s cockiness against him and trick him into sinking into the ocean. Then lets not forget his hax. Super Sonic.

Pinkie still can’t do shit against AoStH Sonic.  
That guy defies physics all the damn time.

Too little feats for Fili-Second.
 
Also depends on which version of Sonic we’re using. Archie Sonic is hilariously broken.

@Agent Tasmania  
Heh, can you imagine Sonic and Pinkie fighting for all eternity? There would be nothing left.

@ThatRandomGuy42  
Both can ignore all matters of physics and reason, no conclusion can ever possibly be drawn.  
We could vote Pinkie since she’s a better character from a franchise that rose magnificently, rather than diving headfirst into an irradiated sceptic tank.  
But on comparison of abilities, both are effectively infinite.

*form

@Agent Tasmania  
Uh, that’s not how Death Battle works. All versions are taken into account.  
Then there is Hyper Sonic which is even faster. Sonic is a very experienced fighter. And like I said, black. hole. He outran one for around a minute in his default from.

@ThatRandomGuy42  
I have no idea what any of these desperate variations of Sonic are.  
We have one form of Filisecond, so only the form of Sonic shown is to be counted.