His nickname is El Mago (The Magician) for a reason.
"It really is a magic act," manager David Ross said with a smile after the game. "He just creates havoc."
It's a play you'll likely never see again.
With Cubs catcher Willson Contreras on second base with two outs in the top of the third inning, Baez hit a routine ground ball to third baseman Erik Gonzalez. Gonzalez's throw to first baseman Will Craig was up the baseline a little, but Craig was able to catch the ball with Baez standing right in front of him.
"My first thought was to go headfirst, pretty much out of the baseline, but the throw got there so early," Baez explained. "I was just trying to make Willy score even though there were two outs."
So Baez began backtracking toward home to avoid the tag. Craig followed him down the line, although he could have simply stepped on first base and ended the inning.
"I just improvise," Baez said. "At the moment I can react pretty fast."
With Baez slowing down as he approached home, Contreras came steaming toward the plate from the third-base side. Instead of tagging Baez, or even going back to first to step on the bag, Craig flipped the ball to Pirates catcher Michael Perez as Contreras came sliding home safely. Baez was still just a couple of feet away from home -- and he signaled Contreras was safe before taking off on a return trip toward first.
"He [Craig] got rid of the ball," Baez said. "I didn't know if I have to [run] because I got into a rundown."
In fact, Baez did have to run. If he hadn't reached first base safely, then Contreras' run wouldn't have counted. So Baez took off while Perez had the ball at home, with Craig just a few feet away.
Perez attempted to throw the ball to second baseman Adam Frazier, who just now was moving over to cover first. The connection didn't happen as the ball went into right field and Baez ended up at second base. He scored on an Ian Happ single.
"It was just a weird play," Pirates center fielder Bryan Reynolds said. "It was just weird."
Baez was credited with a fielder's choice, while Perez was given an error for his throw. According to Statcast, it took Baez 15.54 seconds to reach first base, which is the longest time to first on a fielder's choice in at least the last three seasons.
"I'm pretty good at tagging and not letting people tag me," Baez said.
If the Pirates had tagged Baez or stepped on first at any point in the sequence, the run would not have counted -- even if the out came after Contreras had crossed the plate. Baez's return toward home was within the rules as long as he didn't go out of the baseline or reach the plate. The Cubs' dugout burst out in laughter, and the play instantly went viral.
"He has this way about him," Ross said. "You can call it swag or baseball IQ. He plays the game like a kid. I think that's why a lot of people fall in love with him."
Craig wasn't made available to reporters after the game, while starting pitcher Tyler Anderson admitted no one was yelling to Craig to just tag first base.
"It was quiet out there," he said.
Pirates manager Derek Shelton put the blame on himself.
"That's on me," Shelton stated. "We have to know that. I guarantee you will never see that again while I'm here. ... Our guys have to know the rule."
The play helped the Cubs to a sweep of the Pirates, but the buzz postgame wasn't about the Cubs' four-game winning streak -- it was all about Baez.
"When I called him safe, I remembered that I had to go to first," Baez said. "I was pretty tired."
Ross simply added: "El Mago. That's what it is."