I ain't sayin I beat the devil, but I drank his beer for nothin... and then I stole his song

Totally in control, I lashed out with a violent whipping motion. It felt good.
I watched as the ball buzzed over the net, then quickly dipped as the topspin kicked in.
I posed for a moment, thinking that this must be a clean winner.. then my attention shifted to my opponent.
Although he had been on the other side of the court when the shot was struck, he was now almost to the ball. He moved with unnerving speed, much faster than I had ever seen him move before. While it was a hot day, the air shimmered as he approached the ball, deftly flicking it down the line.
Fuck
I ran as fast as he could towards the ball, preparing for my patented two-hander crosscourt. I began to recoil for the shot, but then I caught a glimpse of my opponent out of the corner of my eye.
He was waiting for it.
I knew that if I hit my crosscourt shot, it would be returned for a volley winner. I knew it as surely as I know my own name.
I abandoned my plan and let instinct take over.
I ripped a one-hander down the line.
It was perfect. Federer, Korda, Sampras. None could have hit a shot any better than this.
The laser shot smacked the sideline and went against the back fence with a loud clang before ricocheting into the corner of the court.
My opponent looked over to the sideline in disbelief before returning his gaze to me.
"Out" he said.

It was a beautiful, sunny day here at Emory University's tennis courts. To their right was a boy and a girl hitting balls. The girl looked Indian and had some nice tits. She had nice form but was pretty slow. Her opponent was a fat, sloppy guy with a beard who had terrible form but would occasionally rip a nice winner. Other college kids were wandered around, going on their merry little ways, many chatting on cell phones about who they had/wanted to/ were going to fuck, and where they would/wanted to get fucked up today.

But that was all in the background now, I could feel anger boil as I looked at this liar in front of me.
"What the fuck are you talking about, that shit was clearly in!" I announced very loudly.
"And that was set point, I won, you owe me $50".
"No," he said, "I call it out, the score is now deuce."
I began walking up to the net, feeling the anger rising and thinking about pummeling this piece of shit with my fists. "Pay me my $50 or I'm GOING TO TAKE IT FROM YOU." I said very loudly. I didn't even notice that everyone around us had stopped playing and was just watching us.

He merely regarded me, a smirk crossing his lips. "And just how would you do that?", he said softly, an undercurrent of amusement in his voice.
"Dude, don't think you....." my voice trailed off as I finally began to see what was going on around us. The air was thickening, becoming hazy. That isn't right though. I can't really describe in words what was happening. Things were just.... dissolving. It was like I ate a sheet of acid at once although my mind was completely clear.

I looked at the two who had been hitting next to us. They were standing and looking at us. The Indian girl's face lengthened to an impossible reptilian mask. Her forked tongue clearly protruded from her fangs?!? The fat one was turning into a gelatinous mass. His eyes were still visible in between the slimy rolls.

I began whirling around, watching with sheer terror as the foundation of my sanity unraveled in front of me, the people who had been milling around earlier had all changed, some had grown opaque wings thick with membranes and were now hovering in the air, others had sprouted additional limbs and scurried on the ground like insects.

I looked back at my opponent who I had once considered a friend. He looked the same as before, but I could tell that there was something behind him, almost as if his entire being was but a costume covering something much larger inside. "What do you want!?!", I screamed, the fear changing my baritone into a hysterical soprano, "WHAT DO YOU WANT!!?".

He merely looked at me, his head tilted quizzically to the side, the smirk still plastered on his face. I could hear the demons closing in on me, I could feel their presence drawing closer, it was not unlike the smell of hot trash, something so vile and unclean that a mere whiff of it could cause you to vomit everything you had inside of you, leaving you dry-heaving on the ground.

Suddenly it hits me, "alright", I yelled, "good call, the shot was out."

As soon as I exclaimed this, all things returned to normal. The birds were chirping and the Sun returned.

He tossed me a second ball. He looked at me and made a squeezing gesture with his thumb and index finger. "It was this close," he said before walking back to the baseline.

I made a mental note to find a new hitting partner for next time.