Nate Bittle scored 23 points and Oregon erased a 17-point deficit to upset No. 11 Wisconsin 77-73 in overtime Saturday in Madison, Wis.The Ducks (20-8, 9-8 Big Ten) also got 14 points from Keeshawn Barthelemy and 13 from Jackson Shelstad. Jadrian Tracey (11 points) and Kwame Evans Jr. (10 points) also reached double figures for Oregon, which trailed 38-21 late in the first half but rallied to secure its fourth straight win.The 20-win season is the Ducks’ 15th in a row.John Tonje led Wisconsin with 22 points. Steven Crowl scored 12 and Nolan Winter chipped in 11 points as the Badgers (21-6, 11-5) took their first loss in six games.Wisconsin led 71-70 with under two minutes left in overtime before Bittle scored four straight points to push Oregon ahead by three with 55 seconds to go. John Blackwell’s layup cut the deficit to one, but Barthelemy responded with two free throws to keep the Ducks up 76-73.Tonje missed a contested 3 with five seconds remaining and Oregon grabbed the rebound. Jadrian Tracey made one free throw in the closing seconds to cap the scoring.The Ducks chipped away at a double-digit deficit in the second half, cutting the Badgers’ lead to 66-61 on an Evans jumper with 2:29 to play. The Badgers had led by double digits for the first 14-plus minutes of the second half.Oregon was within three on a TJ Bamba layup with 56 seconds left, and the Ducks kept it a one-possession game by forcing a turnover on Wisconsin’s ensuing possession.