LONDON—American Sloane Stephens won the battle of former Grand Slam winners against twice Wimbledon champion Petra Kvitova on Monday, ousting the Czech 10th seed from the All England Club with a 6–3 6–4 victory. The 2017 U.S. Open champion came into the match on Centre Court with a 2–1 head-to-head lead against Kvitova, who lifted the Venus Rosewater Dish in 2011 and 2014, but all their previous meetings had been on hard courts. “Obviously seeing the first round, I was like, ‘Oh boy, this is going to be a difficult task’,” Stephens said in her post-match interview on court. “But knowing that I’ll probably play on a big court and feeling good, I was excited to play against Petra.” A run to the quarter-finals in 2013 remains the best result at the grasscourt Grand Slam for 28-year-old Stephens. Playing her first match on grass since the 2019 Wimbledon, the former …