Sophomore Derrick Williams almost single-handedly lifted Arizona past Duke by scoring a career-high 32 points, but will he and his teammates be able to match Kemba Walker and Connecticut in the West Region final? (Lucy Nicholson/Reuters)

Having played on the same team as Derrick Williams during a summer camp in Ohio, Kemba Walker was well aware of Williams’s talents. But after seeing him score 25 points in the first half of Arizona’s West Region semifinal victory over Duke on Thursday night, Walker had another thought.

“The first thing that came to mind was that he might be the best player in the country,” Walker, Connecticut’s star junior guard, said of the Wildcats’ standout sophomore forward. “The best player I have seen this year.”

A few minutes after hearing Walker make that claim Friday, Huskies Coach Jim Calhoun offered a rebuttal: “I’d have to disagree with Kemba for once. I think [Williams] probably is the second-best player in the country.”

The Walker-Williams debate will continue to rage Saturday when third-seeded Connecticut plays fifth-seeded Arizona in the West Region final. While complementary pieces will play a role in the matchup, all eyes will be on two headliners whose wills and unmatched talents have carried their teams to the Elite Eight.

Neither was a first-team preseason all-American, and neither team was ranked in the Associated Press preseason top 25. Williams, one of the nation’s most efficient offensive players, led the Wildcats to a surprising Pacific-10 regular season title, while Walker’s indefatigable play led the Huskies to five wins in five days en route to the Big East tournament title.

“He has had one season that some people don’t have in their whole careers,” Williams said of Walker.

In Thursday’s region semifinal win over San Diego State, Walker scored 36 points, the second most in his three-year career and tied for the most ever by a Connecticut player in the NCAA tournament. Williams, meantime, scored a career-high 32 points, which matched the Arizona record for most points in a tournament game.

The first-half performance by Williams, a robust 6-foot-8 forward who can beat teams inside and outside, was the most impressive of this season’s NCAA tournament. The sophomore, playing a short drive away from where he attended high school in La Mirada, Calif., scored 25 of Arizona’s 38 points to keep the Wildcats within six points of Duke at the break.

He used his athleticism to convert a right-handed follow-up dunk. He used his strength to establish deep position and score close-range shots. And he made 5 of 6 three-pointers in the half, including a 27-footer as time expired.

Arizona’s Solomon Hill said Williams was left with several one-on-one situations in the half because Duke was trying to take away the wing. “He fired at will,” Hill said. “It was a mismatch.”

For his team’s region semifinal matchup with San Diego State, Calhoun said he needed to get up extra early — around 4 a.m. — to prepare for a talent like the Aztecs’ Kawhi Leonard. When asked what his Saturday morning wake-up call would be to prep for Williams, Calhoun said, “I have just booked no sleep at all.”

Arizona, however, will have an advantage in scouting Walker. At one point Thursday against the Aztecs, Walker made a shot, made eye contact with a familiar face off the court and hollered, “They can’t guard me!”

The face in the crowd was Emanuel “Book” Richardson, an Arizona assistant and the former director of the New York Gauchos summer-league program who used to coach Walker. Richardson’s relationship with Walker dates back to Walker’s early AAU days. They still exchange text messages two or three times per week.

“I am fortunate because I understand when he is going to step back, when he is rocking, what he is looking for,” Richardson said of Walker’s style of play, “I have seen it for so long now. Does that mean you can stop it? I’m not sure. Watch what he is doing — left, right crossover. Up-fake, hands up. The command he has with the basketball, you understand what he is trying to do.”

Walker attempted to carry the Huskies early Thursday but missed his first four shots from the field. He didn’t score his first field goal — a layup — until nearly halfway through the first half.

Walker, who scored 130 total points in the Big East tournament, has seen all types of defensive looks his junior season. He felt San Diego State tried to make a point by bumping and bodying him for 40 minutes.

“I felt they were trying to frustrate me,” Walker said. “But I didn’t fall into it.”

Instead, it may be said that Walker simply fell. The momentum-shifting moment occurred with nine minutes remaining and both teams headed to their huddles during a timeout. Walker bumped into the right shoulder of San Diego State guard Jamaal Franklin and hit the floor.

Franklin earned a technical foul; Walker earned two free throws. The play ignited Walker, who scored 14 of Connecticut’s next 16 points during a critical stretch of the game. San Diego State’s Billy White, who has guarded both Brigham Young’s Jimmer Fredette and Walker this season, said Walker is “just an amazing player. He is almost impossible to stop.”

Calhoun has long said that one of Walker’s greatest strengths is his ability to infuse confidence in his teammates based on his words and demeanor. They don’t need to always see him scoring to feed off his confidence. And there is no shortage of confidence.

“As far as big shots, my teammates want me to take those shots,” Walker said. “Everybody on the team, the coaching staff, they want me to take those shots. So as long as they have the confidence in me to take it, I am going to take it with confidence.”

No different from Williams, the other player on the court Saturday with the same unflappable mind-set.