Is this possible? In a perfect storm kind of way, yes, one has to allow that it is possible. I can't recall ever seeing or hearing about it in the real world, but maybe I'll win the lottery, too. It could happen.
How likely is it? Probably on a par with winning two lotteries at the same time. That ten-thousand-hour rule doesn't always apply to every thing, all the time, but the logic is solid. If there is a guy who is relatively adept studying and practicing a thing every day for ten years. somebody who walks in the door and can do that thing better in a few months is either some kind of physical genius ... or a fantasy.
People who like to think it is more likely often point to the Rookie of the Year. Some kid point guard gets drafted into the NBA, he kicks ass and takes names, and outscores a slew of other point guards who have been doing it a long time. Happens every season, doesn't it? and there you go.
Not so much, no.
The newbie in the NBA almost certainly has twelve or fifteen years of practice at basketball. He shot hoops in the driveway or at the gym every day, was on his primary, middle, and high school teams, maybe did a year or four of college basketball, summer camps, and now he's stepped up to the big league. It's a whole other level of skill, top of the pyramid, but he's not some guy on the street who doesn't know a basketball from a bong. Yeah, he has to up his game, but nobody who steps into the NBA and gets to be rookie of the year comes from total inexperience with the sport. Doesn't happen. Or at least it hasn't happened that I can find it.
More likely is, somebody who has been training for two or three years and who has a lot of talent, can stay with players who have ten or fifteen years of practice, but less natural ability.
Michael Jordan was a world-class basketball player, some say in the top three or four ever, but he was a lousy baseball player. How we know this is that he quit basketball for a while and tried to play baseball in the minor leagues. He was smart enough to give that up when it was obvious it wasn't his game. Lot of minor league baseball players were way better than Michael.
Because it has been done so often, and because most people involved in MA know this Perfect Student scenario is primarily hogwash, writers have come up with ways to explain how somebody who doesn't know anything about a thing can get better than somebody who knows a whole lot about that thing in a short time.
Couple quick examples: Tom Cruise, in The Last Samurai. And Bob the Nailer (Bob Lee Swagger), in The 47th Samurai.
In the former, Cruise, an ex-calvary officer from the U.S. is captured while training troops "modern" combat in 19th Century Japan, and over the course of his captivity, learns kendo/iaido well enough to stay with the village's master.
The set-up is that Cruise is a warrior, turned into a drunk by his experiences in battle, but a hero when he was in the saddle and sober. He's quick, and a natural. Able to handle a sword pretty well, albeit a different kind, so learning a new system, he has a good general idea of how to move and not get killed. He has to work at it, but after most of a year, he's there.
Iffy, but still, an attempt to explain something that is a stretch. In writing, this is sometimes called "hanging a lantern on it." If a thing is unlikely or even impossible, but you need it to happen, you do it, point it out, and you let it go.
"Hey! That solid state screen blew up! That's impossible!"
"Yeah, but, dude, look at all that fire and smoke!"
This is the writer telling readers, I know this can't happen, but I did it anyway, and because I did it like this? You can't bitch about it.
In Stephen Hunter's 47 Ronin novel, he knows better than to have his old fart hero, who is retirement age and patched together with pins and plates, learn enough in a few hours to beat a bad ass ninja-type sword-on-sword, so he had a cheat. I won't tell you what it is, in case you want to read the book, but it is very clever, and while it probably wouldn't work, I was willing to suspend my disbelief enough to grin and nod when I saw it.
Supposed to be a movie in the works. I sure hope they don't screw it up.
Mostly, the Perfect Student/Instant Master/Rookie of the Year is not gonna happen, and if s/he does? Better the writer has some clever reason to get away with it than not ...