After its third straight loss, Ole Miss will be out to improve its defense.The Rebels will try to tighten things up on that end of the floor Saturday when they host Southeastern Conference rival Oklahoma in Oxford, Miss.Ole Miss (19-9, 8-7 SEC) is coming off its worst defensive showing under second-year coach Chris Beard, falling 106-76 Wednesday night at No. 1 Auburn. It allowed 11 3-pointers in 21 attempts and permitted at least 50 points in each half, the standard for bad defense.”Just nonexistent defense from Ole Miss,” Beard said. “It’s not just the players. It’s everybody in the program.”Defense was an issue in February for the Rebels, who allow 70.5 points per game but were touched for 80 or more four different times in the month. That included home losses to Auburn and Mississippi State, as well as a win over Kentucky in which Ole Miss committed just one turnover and outgunned the Wildcats 98-84.Six players average double-figure scorings for the Rebels, led by Sean Pedulla’s 14.8 points. He finished with 14 points and four assists at Auburn.While the Rebels look for their 20th win, the Sooners (17-11, 4-11) are trying to aspire to more than the NIT. Their 83-82 home loss Wednesday night against No. 17 Kentucky added up to a missed opportunity as they coughed up a late lead.