Berggren opened the second half with a dunk, but most of the next six minutes belonged to Indiana, which used a 10-0 run to temporarily climb back ahead.
An alert Oladipo had a steal and a layup to tie the score, 40-40, and another Wisconsin turnover led to two free throw tries for Remy Abell, who hit the second for a 41-40 lead.
Dekker broke a 43-43 tie with seven points over the next 50 seconds, including a 3-pointer and a driving layup with 11:11 showing for a 50-43 Badger lead.
Indiana made another run to cut the lead to 52-49, setting the stage for the decisive final six minutes.
"Wisconsin played well; they shot the ball very well," Hoosier coach Tom Crean said. "They made some open ones, and they also made some tough ones ... and they answered the bell every time we made a comeback."
NOTES: Wisconsin, which reached the Big Ten semifinals for the second straight year, also recorded its fourth win over a Top 10 team. The Badgers now have a school record seven wins over Top 25 teams this season. ... It was a tale of two halves on Friday vs. Michigan, as Wisconsin had a season-low 17 points and hit 17.2 percent in the first half, and then collected a season-high 51 points on 60.7 percent shooting in the second. ... No. 3 ranked Indiana, regular season champion and the top Big Ten tournament seed, will make the NCAA tournament with a high seed, but saw its chances for a top seed vanish with Saturday's loss. ... The Hoosiers are 7-1 against nationally ranked teams and 5-0 versus Top 10 teams on the road. ... Indiana coach Tom Crean is 87-81 through five full seasons, but 54-15 since the start of 2011-12. ... The Hoosiers have been ranked nationally for 31 consecutive weeks, the most since Indiana went 71 straight weeks in the rankings from 1989-94. ... The Big Ten coaching fraternity lost one member Saturday when Northwestern fired Bill Carmody after 13 seasons and a 192-210 overall record, four NIT appearances but none in the NCAA tournament.