BERKELEY After three decisive victories, an unexpected defeat and a come-from-behind road win to open ACC play, Cal faces a potent Duke team on Saturday night, hoping to improve to 5-1 for the first time in 10 seasons. We've seen some stretches of good football, Cal coach Justin Wilcox said. Now it's about: What does our best look like? That's what we need to find out. We're going to have to play our best this weekend.