Auburn, which led by 16 points in the first half and seven at intermission, was outscored 42-27 in the second half.
The Commodores, who hit just 1-8 threes in the opening half, made 10-18 in the second half to power their way to a victory that evens their record at 7-7 in the SEC and 15-11 overall.
Auburn, which hit just 33.9 percent from the field, fell to 12-13 overall and 4-10 in the SEC. The Tigers hit just 4-24 threes and couldn't find the range late in the game when they still had a chance to win in the closing minutes.
"It was a tough last 30 minutes, not just the second half," Coach Tony Barbee said. "No matter how bad we shoot the ball offensively you can always have energy to guard, rebound, play tough, talk, communicate and for the last 30 minutes of the game we didn't do that so it was disappointing.
"I tried to warn the guys against a letdown," Barbee said. "It always happens when you play a game like you just had. It is what it is."
What it was on Saturday evening was a poor offensive performance from Auburn's two main scorers. Chris Denson was 3-15 shooting and went 0-8 in the second half. He was 0-3 on treys on the way to scoring 13 points.
K.T. Harrell made just 4-15 field goals and 3-10 treys as he scored 13 points.
Barbee said he couldn't remember the last time that Harrell and Denson both struggled in the same game. "Obviously, we need those guys to set the pace for us offensively, but more than that we need their defensive effort and energy and neither one of those guys brought it."
"It was a disappointing effort and loss by our team starting with me and CD as seniors, and Asauhn," said Payne, who had to switch from No. 2 to No. 55 after getting blood on his jersey in the game. "We just can't have that type of dropoff from a game (Florida on Wednesday) when we played with that much intensity and fight to have a second half like we did to Vanderbilt.
"We were just giving up wide open shots to them," Payne added. "It is just unacceptable."
Allen Payne shoots vs. Vanderbilt.
Auburn's largest lead was at 27-11 on a free throw by Denson with 8:12 left in the half. By intermission the lead was 32-25. Vandy took its first lead of the game on a three-point shot by Dai-Jon Parker with 15:32 left to make the score 40-38.
The Commodores built head to 58-50 with 8:22 left, but in less than a minute the score was 58-55 after a trey by Harrell. However, the Tigers went cold shooting from that point to the end of game and Vandy, which led 58-57 with 5:14 left after a dunk by Atewe, scored 10 points before Auburn scored again with 46 seconds remaining.
"We stopped making shots and we weren't really guarding," Payne said. "I think they outplayed us for the last 30 minutes of the game.
Parker led the Commodores with 21 points as he hit 5-9 treys. Damian Jones added 14 points and walk-on guard Carter Josephs didn't score, but he contributed nine assists with no turnovers in 16 minutes off the bench. "I wasn't used to play that many minutes, but playing well is fun," Josephs said.
Stat of the Game: Vandy's bench, despite having just seven scholarship players, outscored Auburn's bench 17-6.
Worth Noting, Part 1: Auburn won the rebounding battle 41-35 and had 11 turnovers, the same number as the Commodores, but couldn't overcome the difference in field goal percentage.