A set of pictures of a father, who instinctively shielded his son from a flying baseball bat, has gone viral.

On Saturday (March 5), Mr Shaun Cunningham, 37, took his son Landon to his first baseball game - a spring training match in Orlando, Florida between the Atlanta Braves and the Pittsburgh Pirates.

What started out as an early birthday treat for Mr Cunningham's eight-year-old son could have gone horribly wrong, when Pirates outfielder Danny Ortiz lost control of his bat, letting it hurtle towards the stands.

But thanks to Mr Cunningham's quick reflexes, the father and son walked away with minor injuries - and a bat to remember the close shave with danger.

According to CBS Pittsburgh, Landon had been looking down at his phone and texting a photo of the game to his mother when Mr Ortiz lost his grip on the bat.

The father and son were seated just above where the protective netting stopped, when Mr Cunningham caught sight of the flying bat, which seemed to be homing in on Landon's face.

"I didn't have a whole lot of time to think about it," he told WFTV on Tuesday. "It was dad mode, you know, protecting my son. So I just did what I could.

"Realising it was coming for us, and specifically him, and really all I could do was just throw my arm in the way."

The bat smacked Mr Cunningham's wrist as it spun, with its handle hitting Landon on the shoulder.

The split-second moment was caught by Mr Christopher Horner, a photographer for The Pittsburgh Tribune-Review, who was sitting across from the Cunninghams.

"I made this photo of a guy being a hero," Mr Horner said. "But a split-second difference and I would have had an image no one would have wanted to see."

The photos, which were shared via Twitter, have since been retweeted over 4,000 times and liked over 5,000 times.

As the pictures made rounds on the Internet, Mr Cunningham realised how precarious the situation was.

He told WFTV: "It could have been as minor as a broken nose or knocked his teeth out (sic), to a skull fracture."

Landon's mother, too, did not take well to the viral pictures.

"When I initially saw the picture, I wanted to throw up in my mouth," said Mrs Ashley Cunningham.

"As a mother, it's a very scary picture, seeing it all caught in action."

According to the Tribune-Review, Mr Cunningham is a firefighter who played baseball in high school.

Meanwhile, the professional baseball player was unaware of the near-tragedy he had caused until he arrived home.

Ortiz told the Tribune-Review that his wife, who saw the pictures online, said to him: "You almost killed that kid!"

Mrs Cunningham said: "It was a pretty memorable birthday for Landon. Dad's really a hero in his eyes."

Despite the close call, Landon said he had fun at the game and will go to another game, so long as he is sitting right beside his hero.

The boy, who will celebrate his birthday this week, was not sure what to tell other fans about his experience, but his mother was.

"Make sure you pay attention!" she said.

Sources: CBS Pittsburgh, WFTV, Tribune-Review, The New York Times