The 6-foot-6 senior proceeded to produce the kind of pyrotechnics that left No. 15 Butler's four-game winning streak in ashes.
Richardson scored 18 of his 20 points after halftime Sunday and Tennessee overcame a 12-point second-half deficit to beat Butler 67-55. Richardson shot 9 of 13 and had a career-high six steals.
"I just saw we were dead and didn't really have any scoring output in the first half," Richardson said. "KP (Kevin Punter) was playing good, and that was about it, so I decided to come up with it."
Butler (8-2) led 37-25 after Kellen Dunham's 3-pointer in the opening minute of the second half, but Richardson scored the game's next eight points to spark a 12-0 run that tied the score. Tennessee (4-3) took the lead for good on Armani Moore's basket with 6:15 left.
Punter added 18 points as the Volunteers earned their first victory over a ranked opponent since the arrival of coach Donnie Tyndall, who took over Tennessee's program this season.
"It hurts when teams like that hit 3s," Punter said. "It kind of takes the life out of you. But you've just got to stay with it if you want to win. We stayed with it, we kept grinding, they coughed it up a few times and we capitalized."
Butler shot 6 of 23 and committed nine turnovers in the second half. Tennessee outscored Butler 19-5 in points off turnovers.
Dunham scored 16 points, but only two of those came in the game's final 19 minutes. Kelan Martin added 13 for Butler.
"When it comes down to it, I just feel like we got out-toughed in the second half," said Butler forward Kameron Woods, who had seven points and matched a career high with 16 rebounds.
The Vols missed seven consecutive shots during one stretch late in the first half and trailed 34-25 at the break. Tennessee rallied to tie the game at 37-all on Derek Reese's putback with 13:57 left.
Moore later put the Vols up 50-49 for their first lead since it was 6-5 in the game's opening minutes. That started a 6-0 run.
After Butler's Andrew Chrabascz hit a 3-pointer to cut Tennessee's lead to 58-55 with 2:40 left, Reese answered by banking in a 3-pointer to start a game-ending 9-0 run.
"Thank God it went in," Reese said. "The bank is open on Sundays sometimes."
Butler: Butler gave up the most points it has allowed all season. Butler had held eight of its first nine opponents below 60 points.
Tennessee: The Vols used their sixth different starting lineup in seven games. Devon Baulkman, a junior-college transfer, made his first career start and had three points and three rebounds in 18 minutes.
Tennessee shot 59.3 percent (16 of 27) in the second half after shooting just 39.1 percent (9 of 23) in the first 20 minutes. ... Butler entered the day with a turnover margin of plus-5.9, but it committed 14 turnovers while forcing only seven against Tennessee.
QUOTE OF THE DAY
"I don't know that I've ever been more proud of a group of guys than I was today, just because you're playing a nationally ranked team with the tradition and history of Butler. The first half didn't go our way. Early in the second half, it didn't start exactly right and they just battled, clawed and found a way."-Tyndall
Butler: Saturday vs. Indiana in Crossroads Classic at Indianapolis.
Tennessee: Wednesday at North Carolina State.
Ohio holds off St. Francis (PA) behind Sears
— Mark Sears scored 24 points and Ben Vander Plas scored 13 and Ohio held off St. Francis (PA) 78-75 on Saturday.
Woodrich sparks Cleveland State past Wright State 85-75
— Jayson Woodrich came off the bench to score 17 points to carry Cleveland State to an 85-75 victory over Wright State in Horizon League play on Saturday.
Toney, Notae score 15, No. 10 Arkansas beats Little Rock
— Au’Diese Toney scored 18 points and JD Notae had 15 to lift No. 10 Arkansas past Little Rock 93-78 on Saturday.