The score was tied 2-2 and there were two outs when Alex Ríos decided to keep running past second base.
Ríos scored the go-ahead run without a play, and the Puerto Ricans rallied to oust Italy from the World Baseball Classic with a 4-3 victory Wednesday night.
The Puerto Ricans went hitless in their first 12 at-bats with runners in scoring position but still overcame a 3-0 deficit to score once in the sixth inning and three times in the eighth.
"With the lineup we had, it was a matter of time before we started scoring," Puerto Rico manager Edwin Rodriguez said. "Everybody was putting a little pressure on themselves. The coaching staff had to take it and make it seem like we were calm."
Ríos crossed the plate standing up for the final run on a grounder to the shortstop, which Jack Santora backhanded before throwing wide to first.
That was one of four misplays by Italian shortstops, including three in the sixth by Anthony Granato, who allowed an unearned run to score and was then replaced by Santora.
"We had problems scoring runs, but we were putting pressure on them," Rodriguez said. "The breaks went our way, and we took advantage of them."
Yadier Molina had three hits for the Puerto Ricans and scored their first run.
"We are only in March," Molina said, "and you're facing pitchers throwing 95 and 96 mph. You see it on a daily basis. I looked for my hits, and the team followed me."
The Italians blew a 4-0 lead in a loss Tuesday to the Dominican Republic.
"It was the end of the road for us," Granato said. "That's always disappointing when something like this happens. Nobody likes to end it. You always want to be the last man standing. It didn't happen for us. It hurts but what can you do? That's the way it goes."
The Puerto Ricans advance to Friday's game against the winner of Thursday night's game between the United States and Dominican Republic. R.A. Dickey will start for the U.S. team, and Minnesota Twins right-hander Samuel Deduno starts for the Dominicans.
Hiram Burgos (1-0) pitched 3 2-3 scoreless innings for Puerto Rico.
"We had faith as a team," Burgos said. "I tried to keep us in the game and give us a chance to win, and the batters did what they had to do."
Fernando Cabrera struck out Alex Liddi with a runner at first for his second save, and the Puerto Ricans poured out of their dugout, jubilant and relieved.
"There's a lot of emotion," Rodriguez said. "When you're playing for your nation, we know everybody is watching back home."
Italy's Anthony Rizzo broke a scoreless tie with a three-run double in the fifth, and Puerto Rico trailed 3-1 going into the bottom of the eighth.
Carlos Beltran led off with a walk, took third on a single by Molina and scored on Mike Aviles' groundout.
Ríos singled off Brian Sweeney (0-1) to put runners at the corners, and he took second when Luis Figueroa hit a sacrifice fly to make it 3-all. Andy Gonzalez beat out an infield hit when Santora threw wide to first baseman Rizzo, and Ríos came around to score.
"I saw him rounding," Rizzo said. "I figured it was going to be a tough out. The game was just a funny game. Tip your hats to the Puerto Ricans for not giving up."
With the retractable roof open at Marlins Park and the temperature in the 60s, fans in the crowd of 25,787 blew horns and whistles and banged drums to create a festive cacophony.
Puerto Rico's Giancarlo Alvarado took a shutout into the fifth. Granato singled with one out, and Nick Punto reached on catcher's interference by Molina. After Chris Denorfia singled to load the bases, Xavier Cedeno replaced Alvarado and gave up Rizzo's double.
The Italians, who had only six major leagues on their roster, reached the second round for the first time.
"It was good for this team," Rizzo said. "Everyone had written us off that we shouldn't be here. We earned respect."
Based on reporting by the Associated Press.