The junior guard from Melbourne, Australia, finished with 28 points, including 11 in the final three minutes to lead the Vandals to their second straight Western Athletic Conference tournament title, defeating Seattle for the second consecutive year 75-67 Saturday.
Barr was 9 of 16 from the field, and 9 of 10 from the free-throw line, including 6 of 7 in the last 2:48. She was the tournament's Most Valuable Player.
"The opportunity was there (late) and I just tried to take it and help out my team," said Barr, who was one point shy of a career high. "We just wanted to prove last year was not a fluke. We had that to prove to everyone."
Alyssa Charlston added 17 points and six rebounds for the Vandals (25-8). Idaho also won 18 of 19 against conference teams and defeated Seattle in last year's title game.
This will also be the second straight NCAA appearance for coach Jon Newlee, whose team was sent to Connecticut for the first round of last year's NCAA tournament.
Newlee points to team chemistry for the Vandals' success.
"Their calmness under pressure and their ability to handle all the pressure they went through (this year) for a pretty young team they're so resilient," he said. "They're great to be around. We don't have that drama stuff. They all know their roles. They don't focus on individual stats."
And now Newlee hopes the tournament committee gives Idaho a little more respect this year.
"We had close losses to (Gonzaga) and (California)." he said. "I feel we deserve a 10-12 seed. We get punished for the league we're in."
The Vandals were playing with added emotion this weekend as Connie Ballestero's uncle died Thursday in a Las Vegas hotel room. Her family made the trip to watch her play in the tournament. Ballestero, a starting guard, had six points. The team wore black patches on their jerseys to honor him.
Idaho won both regular-season meetings, most recently at Seattle on March 1, 60-57. The Vandals are having their best season in the win column since 1985-86, when they went 26-5 and won the women's NIT championship.
Ashley Ward led the third-seeded Redhawks (16-16) with 17 points, and Sylvia Shepard had 14 points and four blocks.
"We played our best basketball (in March)," Seattle coach Joan Bonvicini said. "We had a season where we've grown a lot to get us to this point. We need to finish the job and get us a championship."
After leading 31-29, Idaho never trailed by more than two points, and led by as many as eight in the second half.
Idaho was 20 of 26 (77 percent) from the free-throw line and Seattle was 11 of 21 (52 percent).
The Vandals jumped to an early 20-6 advantage.
But the Redhawks ended the half on a 21-7 run, tying it at 27 before two Vandal free throws ended the first half. Both teams shot 10 of 25 from the field in the half.
"We didn't start the game with a lot of energy," said Ward, who fouled out with 2:48 left. "Once we found out Idaho was here to play, we decided to pick our game. We started to hustle."