KNOXVILLE, Tenn. -- No. 20 Kentucky blew a 21-point first-half lead en route to being upset 84-77 by Tennessee Tuesday night.

The Wildcats (16-6, 6-3 SEC) jumped out to a 34-13 lead with 5:32 left in the first half behind 12 points from senior forward Alex Poythress.

But then Tennessee (11-11, 4-5) went on a 10-0 run to slash the lead and closed the first half by outscoring Kentucky 29-2 to make it 42-36 at intermission. Senior guard Kevin Punter paced the Volunteers with 12 points, senior forward Armani Moore had 10.

Tennessee's comeback bid was finally complete when the Volunteers took a 56-54 lead with 14:01 remaining in the game. At that point, Punter had 17 points to lead a 43-20 Tennessee run. Punter would go on to score 10 more points to push Tennessee to the seven-point victory.

"Our guys really deserve all the credit in the world, the way they hung in and hustled," Tennessee first-year coach Rick Barnes said. "They weren't playing very well early, but they stayed with it. They really did. There wasn't one person that played that game that didn't help us some way, somehow. For us to come back obviously was a terrific win for us."

All told, from the point Tennessee trailed by 21, they outscored Kentucky 71-43.

"We had them down 21, and they came back and beat our brains in," Kentucky coach John Calipari said. "So you think about it. They end up beating us by 30 in about 25 minutes, and it could have been 50. You got to give Rick credit. They fought like heck. How about getting down 21 and not stopping? It shows what a good coach he is."

Punter finished with 27 points. Moore had 18 and freshman forward Admiral Schofield had 11. As a team, Tennessee shot 41.1 percent from the field but 42.1 percent from 3-point range with eight made 3-pointers. They outrebounded Kentucky 37-36.

The 21-point lead is the largest blown by Kentucky under a Calipari-coached team. Overall, it is the biggest collapse since being up 20 and losing in 2002.

"Historically -- you may have to look back -- my teams get up 10 and it's like 100-2," Calipari said, exaggerating the point. "So I'm coaching a different kind of team."

Kentucky was led by freshman guard Jamal Murray with 21 points. Sophomore guard Tyler Ulis had 20, Poythress, 14, and freshman guard Isaiah Briscoe, 10. UK shot 41.9 percent from the field, 31.8 from 3-point range.

One key stat, just as it was in Kentucky's loss at Kansas on Saturday, was at the free-throw line. UT made 30-34, Kentucky 18-23.

Kentucky, fresh off an overtime loss at Kansas on Saturday, returned to conference play needing a win to keep pace in the SEC. Instead, the Wildcats are now two games behind Texas A&M with Florida coming to Rupp Arena on Saturday.

"I'm just trying to demand that they do it the right way and I'm asking them why would you do that? Why wouldn't you do what we're teaching?" Calipari said. "Why are you trying to break off? And then when they do the same thing three times, then I get a little more aggressive. Then I'm -- obviously you're not hearing me so I'm gonna say this louder and a little bit closer to your face, so you hear what I'm saying.

"They're fighting me. They haven't surrendered to it yet," Calipari said. "They're still, 'My stuff works.' At what point is it gonna work? So they haven't surrendered to it."

Tennessee, which snapped a two-game losing streak, travels to Arkansas on Saturday.

NOTES: Rebounding is the key to Kentucky winning and losing. In 16 victories, UK has a plus-10 rebound advantage. In six losses, the margin is minus-3.5, nearly a 14 rebound swing. ... Tyler Ulis is the first UK player since 1986 with four or more assists in 15 straight games. ... Over the last five games, Derek Willis is averaging 10.8 points and a team-high 8.3 rebounds. ... The two coaches are the two winningest active head coaches in the SEC: 615 wins for UT's Rick Barnes, 609 for UK's John Calipari.