St. Louis Cardinals fans were furious with Pete Alonso for throwing away Masyn Winn's first hit to the crowd. It turns out, Alonso felt horrible after the fact.

Thankfully, Masyn Winn did eventually get his first MLB hit ball back, as Cardinals fans were nice enough to lend it to the rookie in exchange for (one would assume) some memorabilia. Yet, this all could have been avoided if Alonso didn't have his self-described 'brain fart' in the moment.

"I feel awful," Alonso said after the Mets' 7-1 victory, per the New York Post. "I know it sounds stupid, but it's just a bad brain fart. … I feel like a piece of crap. In the heat of the moment you just kind of get lost."

Alonso apologized to Winn in the moment, and the Mets handled the matter as classily as they could. Francisco Lindor was seen chatting with Winn on the basepaths, as well, telling him to soak it all in.

"I'm happy he's got the ball, but I feel like an idiot," said Alonso. "That was a complete bonehead move and I feel awful."

Mets slugger Pete Alonso feels awful for discarding Masyn Winn's first Cardinals hit

The Mets slugger also received plenty of flack from Nolan Arenado and Paul Goldschmidt, who played with him on the Team USA World Baseball Classic team. Per Alonso, the Cards duo shouted "Pete, what the hell are you doing?"

"I'll never throw a ball into the stands again — I will just roll every ball into the dugout when they are going to switch it out," Alonso continued.

While Alonso received plenty of hate from Cards fans on social media, it appears to have been an innocent mistake by the Mets star which led to Winn's ball being discarded like any other.

Alonso is relatively lucky that this game took place in St. Louis, as Cardinals faithful were well aware of the importance of Winn's first hit. In Queens, that ball might've been lost forever.