KNOXVILLE, Tenn. -- Tennessee forward Bashaara Graves can't explain her tendency to have her best performances in the Lady Vols' biggest games.
She just wants to make sure the trend continues for a couple of more weeks.
Graves scored 21 points and had 14 rebounds as Tennessee withstood a late rally to defeat Pittsburgh 77-67 in an NCAA tournament second-round game Monday night.
The 6-foot-2 junior's double-double came two days after Graves had a career-high 24 points in a 72-61 first-round victory over Boise State. Graves also had 22 points at Notre Dame and 20 points at South Carolina this season, although Tennessee lost both games.
"It just happens," Graves said. "I don't think it's (that I have) a different mindset. Everyone else says they can tell when I'm quiet during warm-ups that I'll have a good game, but I don't think anything like that."
The second-seeded Lady Vols (29-5) improved to 56-0 in NCAA tournament home games and advanced to a Spokane Region semifinal Saturday against No. 11 seed Gonzaga (26-7).
Tennessee is the only program to appear in all 34 NCAA tournaments and has reached the regional semifinals every year but 2009, when it lost to Ball State in the opening round.
Tennessee withstood a brilliant performance from Pittsburgh senior Brianna Kiesel, who scored 24 of her career-high 32 points in the second half for the 10th-seeded Panthers (20-12).
"Just playing (Tennessee) today and having the honor of playing one of the best teams in the nation, it was just a great, amazing game," Kiesel said. "I couldn't have asked for a better way to go out."
After trailing by 14 with 4½ minutes left, Pittsburgh (20-12) cut the lead to 69-65 on Kiesel's three-point play with 37.8 seconds remaining. Ariel Massengale went 6-of-6 on free throws and made a steal in the final 37 seconds to seal Tennessee's victory.
"What a gutsy performance by their point guard," Tennessee coach Holly Warlick said. "She was incredible. She was a handful. That's what you do when you get to this point. You battle and play hard."
The Lady Vols never trailed all night because one player from each team didn't come close to repeating her first-round performance.
Tennessee's Cierra Burdick had gone scoreless against Boise State, although she did have 11 rebounds and five assists. She made the game's first basket Monday, and finished with 14 points and 10 rebounds.
Pittsburgh's Stasha Carey, who had 16 points and 13 rebounds in a 51-40 opening-round triumph over Chattanooga, had no points and three rebounds against Tennessee.
"I was just trying to stay positive," Burdick said. "I knew today I had to bounce back. It was nice to see the ball go through."
Massengale had 16 points and Andraya Carter added 10 for Tennessee, which outrebounded Pittsburgh 46-29. Yacine Diop had 18 points and nine rebounds for Pittsburgh.
Tennessee went on an 11-0 run to take an early 15-4 lead and owned a 35-23 advantage at halftime. Pittsburgh crept closer when Kiesel sparked a 9-0 spurt to start the second half.
After Tennessee regained control and built a 14-point lead, Kiesel led one more rally.
Graves made sure Tennessee survived.
"Big-time players step up in big-time moments and make big-time plays," Massengale said. "That's what Bashaara is continuing to do for us."
Pittsburgh: This marked the fifth time overall and the second time in NCAA tournament play that the Panthers had faced Tennessee. The Panthers have lost all five meetings, including a 68-54 decision in a 2007 NCAA second-round game at Pittsburgh. Tennessee went on to win the national title that season.
Tennessee: In their final game at Thompson-Boling Arena this season, Lady Vols set a school record with their 18th home victory of the season. This marks the 12th time Tennessee has posted a perfect home record, but the Lady Vols didn't play as many as 18 home games in any of those other seasons.
Tennessee has a plus-17½ rebound margin through its first two NCAA tournament games.
"I asked (Kiesel) going down the hall if she wanted to go to Spokane with us," Warlick said. "I'm sure we'd find some kind of uniform for her."
Pittsburgh heads into the offseason needing to figure out how to replace Kiesel, who ends her career as the only player in school history with more than 1,500 points, 500 rebounds and 400 assists.
Tennessee faces No. 11 seed Gonzaga in a Spokane Region semifinal Saturday.