A 9-year-old Isaiah Davis stood on second base, his Joplin Miners baseball team winning 5-4 in the championship game of a tournament when the first tornado warning siren went off.

“Everyone kind of like paused,” Davis recalled last week. “No one thought anything of it. We went back to playing. Two minutes later it went off again. The ump ended up calling the game.”

Little did Davis know that his life and his family’s lives were about to change.

That baseball game was on May 22, 2011.

Minutes later, one of the deadliest tornadoes in United States history hit Davis’ hometown of Joplin, Mo.

Davis, now a rookie running back with the Jets, recounted that day recently for The Post.

After the baseball game was canceled, Davis returned home with his father and his brother while his mother went to get food.

Despite the tornado warning, the Davises were not overly concerned.

Isaiah prepared to get in the shower as his mother put the food out in the living room.

Then, everything changed.

“I remember a big boom,” Davis said.

Cedric Davis, Isaiah’s father, looked out the front door of their house and saw the trees bending in a way he had never seen before and the sky turned black.

“He started yelling, ‘Get in the hallway, get in the hallway, get in the hallway,’ ” Isaiah Davis said.

Cedric grabbed the top mattress off of a bunk bed and threw it over Isaiah and his brother, McKinley, in the hallway.

“The ground, the walls, everything in the house started shaking,” Cedric Davis said Thursday. “Luckily, a blessing, I went into survival mode.”

Davis’ mother, Brandi, stood by the kitchen window in shock and not moving.

Cedric screamed her name and finally she snapped out of it.

“She ran through the living room and dived under with my two dogs that were outside as the tornado started to tear the house apart,” Isaiah Davis said.

The family stayed under the mattress, which was wedged perfectly between two walls, for three to four minutes as destruction surrounded them.

“My dad was praying and screaming that if it took anybody, it would take him and not us,” Davis said.

They remained under the mattress for several minutes until they knew the tornado was not coming back.

Cedric cleared debris off the mattress and moved a tree that had fallen on it.

When they emerged, they saw just a few walls of their home remaining. There was total destruction around them.

Cedric’s quick thinking saved the Davis family.

He said he had thought about a plan for a tornado before and realized the mattress wedged into the hallway would provide cover.

“I’m glad I didn’t freeze up,” Cedric Davis said. “I was able to get everybody into a safe spot.”

Isaiah and his family soon went to his grandparents’ house, driving through yards to avoid fallen power lines and seeing what the tornado had done.

They had lived through an EF5 tornado, the strongest tornado on the scale, with winds of over 200 mph.

The tornado killed 158 people and destroyed 4,000 buildings.

As 9-year-old Isaiah sat at his grandparents, he began to understand what just happened.

“I remember looking at my mom crying,” Davis said. “We were homeless. We didn’t have anything. We lost everything. … At 9 years old, you really can’t do anything to help your parents. You’re just thinking about you don’t have anything. Everything you had is gone. No house, nothing.”

The Davis family spent a month moving from hotels to friends’ homes until their insurance company found a temporary home for them before they bought a new house on the other side of Joplin.

Davis wondered why they did not move back to where their old house was.

“I asked them why we didn’t move back in there and they were like, ‘Because of the memories,’ ” Davis said. “I didn’t understand that at the time, but now I can see why they didn’t want to.”

For years after the tornado, Isaiah feared another one.

“Anytime there was any kind of thunder, I had to seek shelter,” Davis said.

Davis said he and his family became tornado experts.

The biggest lesson he took from the tornado was from watching his father think quickly and grab the mattress that probably saved their lives.

“Thankfully my dad thought quick,” Davis said. “What I took away from it was always having a plan and always taking care of family. We didn’t think anything of it and I felt like it almost went the worst way possible. I feel like now me and my family wherever we’re at situation-wise as far as the weather goes, we’re always going to have a plan.”

Davis went on to become a top football player in Joplin and then at South Dakota State.

The Jets selected him in the fifth round of this year’s draft.

Davis has come a long way since that harrowing day in 2011.

He is now catching no-look passes from Aaron Rodgers and preparing to play his first NFL game.

In May, 13 years after nearly losing it all in the tornado, Davis had a moment when he realized how far his journey had brought him.

“It was the first day of spring practice and Tyrod [Taylor] put his hand on my left shoulder in the huddle,” Davis said. “I almost forgot the play and I was like, ‘Man, I’m really here.’ This has always been a dream of mine.”

For the Davis family, May 22, 2011, is a date they will never forget and it forever changed their outlook on life.

“We could have been gone that day,” Cedric Davis said. “I don’t like to say lucky. We were blessed to still be here. I don’t take anything for granted. I try to enjoy every day.”