Barry realizes that he is not just fighting a guy who is just muscle. He is fighting a guy who knows magic.
Magic is one hell of a force. Something that makes no sense whatsoever because it goes completely against common sense.
So it's not surprising to see Ares, an actual god, use Magic to dodge his super-speed attack.
"You are a fast mortal, but I have fought against beings much faster than you," Ares says with arrogance as he looks down at Barry.
'I doubt that,' Barry thinks. He can guess who Ares is talking about, Hermes, the real god of speed.
And there is no doubt about Hermes being fast enough to travel faster than the speed of light. In fact, Hermes has bested the Flash multiple times in the comics. But our Barry is not just any Flash. He is the speed force itself, and like the speed force, his speed has no limits.
So no matter how fast Hermes is, his divine power still has limits, unlike the speed force.
"Aren't you the god of war? Why do you talk so much instead of fighting?" Barry shouts at the god.
"As you wish, Mortal. I will show you the wrath of a God," Ares says, and the winds get more extreme just from the influence of his rage.
He raises his hand and conjures energy around them in an instant, and shoots a beam at Barry. This beam has the power of divinity behind it, making it the most dangerous thing Barry has ever faced off against.
Will it kill Barry? No, because he is immortal. But it can definitely destroy his mortal body, which would then have to be rebuilt back from atoms.
Plus, this beam is traveling at the speed of light.
Barry sees it. His senses flare up, giving him warning signals. Lightning flashes in his eyes, and he enters Flash Time.
Even inside Flash Time, the beam is traveling faster than anything he has ever seen. To dodge this, he needs to move faster than the speed of light.
He can feel his power, his origin, coursing through his entire being. He can feel himself getting charged up, and so he moves.
As he moves, he sees space around him getting pulled along with him as if he just ran through a very thin sheet of silk.
This is the barrier of time. Well, it cannot be seen, but since Barry is moving faster and breaking the time barrier, it is affecting the space he is occupying.
This is the fastest, Barry has ever moved.
Barry manages to move to the side and dodge the divine beam, which hits the ground and gets vaporized, leaving behind a massive, smooth crater.
Though Ares can shoot this light-speed beam, he cannot see at light speed. So the only thing he sees is Barry suddenly teleporting and dodging the divine beam.
"Impossible!" Ares shouts in disbelief.
Even if one had the power of teleportation and could move from one place to another in an instant. It would still be impossible to dodge this divine beam.
To react to this beam, one needs to be faster than the beam itself. And a teleporter would never be able to process faster than the speed of light. A teleport would get hit before he even realizes what hit him.
But Barry just dodged it.
This is the power of the speed force.
To actually see something that is moving at the speed of light doesn't make sense at all, because for one to see, light first has to bounce off that object or thing. But under the influence of the Speed Force, Barry can see things happening faster than the speed of light.
It's more like seeing into the future of his surroundings and everything that will happen in it through his own eyes.
"How did you do that?" Ares asks in disbelief.
"You know I am not the only one you need to worry about, right?" Barry says, and Ares immediately realizes what he means by this, but it's too late. Diana's fist smashes into Ares's head.
Sending the god crashing into the ground.
Seeing his chance, Barry runs towards Ares. As Ares tries to get back up to his feet after getting his head rattled by Diana's punch, the god doesn't know his head is about to be viciously punted.
Barry runs at Ares with super speed, who has his hands on the ground, trying to push himself up, but the very immediate moment in time, Barry punts the shit out of Ares's head.
His head snaps faster than his muscles are used to moving, before his entire body shoots through the air.
Barry arrives next to Diana and looks her in the eyes.
"Do you know how to get rid of him?" Barry asks. Since Ares is a god, he should also be immortal, and Barry doesn't know how to kill an immortal god, so if there is anyone who would know how to kill a Greek god, it is someone who belongs to the same pantheon as him.
"I do," Diana says with determination in her eyes.
"Good, then the best way to take him on is by overwhelming him. I will distract and annoy him with my speed, and when you see the opening, do what you have to do." Barry comes up with a simple plan, but also an effective one.
"I understand," Diana says.
"Good, let's go kick a god's ass," Barry says, grabs Diana and runs her to Ares, who is still flying through the thick forest, mowing down trees in his way.
Barry might have kicked him a little too hard.