Let's relive Roberto Osuna's dominant run during the 2015 postseason -- at age 20

Baseball is a notoriously unforgiving game, especially at the highest level. It almost always takes time for players to find their footing and excel -- even baseball demigod Mike Trout hit .220 in his first Major League season. Waiting, however, has never really been Roberto Osuna's style.
It may seem like the Blue Jays' closer has been around for a while, but he turns just 23 years old on Wednesday. He broke into the Mexican League at 16, only to be snatched up by Toronto after a couple of months and breezed his way through two levels of the Minors the next year. The Blue Jays gave the righty a chance to be a starter, but he struggled in Class A Dunedin in 2014, so that plan was quickly scrapped. Instead, Osuna began the '15 season in the bullpen with the big league club. By August, he'd nailed down the closer's job.
That fall, he found himself in his first postseason, the youngest closer in baseball pitching in front of a rabid crowd experiencing its first taste of October baseball in over 20 years. He took that opportunity to become a star:

Osuna's first postseason appearance came in Game 2 of the American League Division Series against the Rangers, and he was brilliant, firing two perfect innings to keep his team in the game. But the Blue Jays eventually fell, 6-4, and headed to Texas down 2-0 in the series. Two scoreless ninth innings from Osuna later, they were headed back to Toronto for a do-or-die Game 5:

You probably remember a lot about that Game 5, from Rougned Odor scoring one of the weirdest runs in postseason history to Elvis Andrus' crucial errors to José Bautista's bat flip to end all bat flips. What you might not remember, however, is that after Bautista's dinger gave Toronto the lead, the Blue Jays came pretty close to handing it right back: In the bottom of the eighth inning, Aaron Sanchez gave up a single to Prince Fielder and a walk to Mitch Moreland, bringing Josh Hamilton up as the potential tying run.
Manager John Gibbons brought Osuna in to get out of the jam, and he did not disappoint: 

He struck out both Hamilton and Andrus, then slammed the door with two more K's in the ninth:

Toronto fell to the Royals in the AL Championship Series, with Osuna allowing the series-winning run in Game 6 thanks to some superhuman baserunning from Lorenzo Cain, but the righty's first postseason was nonetheless impressive: 8 1/3 innings, six K's, three hits, two runs. He completed his leap to elite closer the next year, saving 38 games with a 2.68 ERA in 2016 -- while throwing nine more scoreless innings in October. 
At this rate, he'll probably have a Cy Young Award before he can rent a car.