North Carolina’s Kendall Marshall (O’Connell) and Kentucky’s Brandon Knight are two of the top young point guards in college basketball.

In the view of most college basketball coaches, nothing’s quite so valuable as an experienced point guard. The best boast a rare combination of bravado and selflessness — able to decide in an eye-blink whether to take a critical shot or find the player who can, in addition to dictating the game’s tempo, calling the plays and taking command in the huddle.

Yet North Carolina and Kentucky have reached the NCAA tournament’s final eight by putting this all-important job (and with it, much of their fate) in the hands of two freshmen.

When second-seeded North Carolina (29-7) faces No. 4 seed Kentucky (28-8) in Sunday’s East Region final, the showdown between 19-year-old Kendall Marshall and 19-year-old Brandon Knight may well decide which storied program advances to the Final Four in Houston.

Though their physiques are nearly identical (both are 6 feet 3 and 185 pounds, give or take a pound), Marshall and Knight have different strengths, and as a result, approach the job differently.

Marshall, a Dumfries native who led Arlington’s Bishop O’Connell to a Virginia Independent Schools championship in 2010, is hard-wired to pass first and leads the ACC (as well as all freshmen in the nation) with 6.2 assists per game.

Knight, who collected nearly every national accolade as a prep standout in South Florida, is hard-wired for taking clutch shots. In two of Kentucky’s three NCAA tournament games, Knight hit the wining basket — one with two seconds remaining, the other with six seconds — to keep the Wildcats’ season alive.

But without the dramatic strides each has made in recent months, neither team would have gotten this far.

Marshall’s emergence is inseparable from North Carolina’s.

He started the season as a backup and wasn’t named the Tar Heels’ starting point guard until two months ago, following the team’s lackluster performance in a 78-58 loss at Georgia Tech on Jan. 16. It was North Carolina’s fifth loss of the season. Since then, the Tar Heels have lost just two of 19 games, and their offensive productivity has soared. In the three ACC games before Marshall took over, the Heels averaged 61.3 points per game. Since, they have averaged 78.2.

Within days of the lineup change, junior Larry Drew II, whom Marshall supplanted, transferred.

“When I put Kendall in the starting lineup, I felt as a coach I needed to do something because I wasn’t pleased with what we were doing, particularly the way we played at Georgia Tech,” North Carolina Coach Roy Williams said Saturday.

But the more dramatic turning point came after Drew left, the coach said, which clarified matters. “It was Kendall’s team as a point guard to run, and everyone knew that,” Williams said.

Among the chief beneficiaries was North Carolina’s highly touted freshman forward Harrison Barnes, who had been criticized for a slower-than-anticipated start. In each of the Tar Heels’ three NCAA tournament games to date, Barnes has scored 20 or more points. He cites Marshall as a reason why.

“Kendall does a great job of getting me the ball close to the three-point line, opposed to earlier in the season,” when Drew started, Barnes said. Drew’s passes “were close to half-court or 10 feet off the top of the key, so it makes it difficult to attack and difficult to get into a good shot. What Kendall’s penetration does as a shooter, he allows me to get into a rhythm which allows me to make a lot more.”

Marshall’s pass-first mentality can be traced to drills and games his father devised when Kendall was a youngster at Dale City’s Boys and Girls Club. Mindful that his son wasn’t going to be exceptionally tall, Dennis Marshall figured he could still become an exceptional player if he could do one thing — specifically, pass the ball — better than everyone else.

“So I put him in situations where he had to think about passing,” Dennis Marshall said. “I’d have him play games at the rec center and tell him, ‘You guys have got to win, but you’re not allowed to score.’ It forced him to create shots for his teammates.”

Knight, among the nation’s most coveted high school recruits, arrived at Kentucky needing no coaxing when it came to shooting the ball.

The challenge facing Coach John Calipari was two-fold.

He had to get Knight to embrace the notion of running an offense rather than simply starring in it. And he had to get him to play defense, a chore that high school phenoms are rarely burdened with. That meant getting him to hustle even when the player he was assigned to guard didn’t have the ball, and it meant getting him to talk on the court.

“I watched him play a bunch in high school, and he never spoke,” Calipari said of Knight. “Well, you can’t be that way as a point guard; you have to be in huddles talking.”

And when a game hangs in the balance, Knight makes Calipari’s late-game play-calling easy.

It’s not that the freshman point guard makes every shot he lofts or even half. He just has a way of making the ones that matter — as he did against in Kentucky’s first-round nail-biter over Princeton, going 0 of 7 from the field until he hit the game-winner with two seconds to play.

“He’s one of the most conscientious, hard-working players that I have been around, so he feels that he will make that shot,” Calipari said. “More importantly, why I put the ball in his hands, he is not afraid to miss it. If you really want to be that guy, you have no fear: ‘If I miss this shot, I miss it. I am not afraid to miss this shot. Life will not end.’ ”