Knowing nothing of the trails and terrain in Boston’s Franklin Park, Lauren Centrowitz came blindly to the starting line in the Women’s Championship 5K race at the 22nd Annual Mayor’s Cup. What she lacked in preparation, she redeemed in will. “I just decided to make it hurt,” Centrowitz said. “I didn’t know anything about the competition or the course.” The 25-year-old took clear ownership of the lead after 3 kilometers, and never looked back. “There were a lot of good runners out here today. It was a surprise to pull away when I did. It’s always difficult to run by yourself. I’m happy with the win.” The seven-time All-American from Stanford University earned $600 for her victory, and $300 for finishing as the top American.