After three losses this year by a combined eight points, Northwestern has found the finishing touch, winning three straight games, all against power conference teams.Northwestern (9-3) tries to extend its streak Sunday in Evanston, Ill., when it takes on Northeastern (8-4) in the final nonconference game for each team.Making a difference recently for the Wildcats has been their defensive pressure and care of the ball.During the Wildcats’ three-game run, which included a 70-66 win in overtime against then-No. 19 Illinois, they forced 45 turnovers while committing just 18. That translates to a 43-16 edge in points off the mistakes.”That’s something we’ve really talked about as a team,” Northwestern coach Chris Collins said after an 84-64 win over DePaul on Dec. 21. “We’re a really good defensive team and we need to turn some of those live-ball turnovers, so points can come a little easier.”Brooks Barnhizer has done a little bit of everything during the Wildcats’ mini-streak, averaging 19.3 points, 10.7 rebounds, 3.3 steals, 3.3 assists and 2.7 blocks.Nick Martinelli has continued to excel with his rare skill set, combining crafty work in the paint with his expanded range from the perimeter.The left-hander has averaged 22 points in the last three games. For the year, Martinelli has hit 14 of 25 shots (56 percent) from beyond the arc.For Northeastern of the Coastal Athletic Association, this is the only game on its schedule against a power conference team. In 19 seasons under coach Bill Coen, Northeastern has pulled off nine victories over major conference foes.