Japan’s Ena Shibahara and Dutchman Wesley Koolhof beat Belgium’s Joran Vliegen and Norway’s Ulrikke Eikeri in straight sets to win the French Open mixed doubles championship on Thursday. The second seeds, Shibahara and Koolhof, clinched the 7-6(5), 6-2 victory in 1 hour, 29 minutes on Court Philippe Chatrier. The 24-year-old Shibahara is Japan’s first mixed doubles champion on Roland Garros’ red clay since Rika Hiraki teamed with India’s Mahesh Bhupathi in 1997. Shibahara, who is from California, played for Japan at last year’s Tokyo Olympics. “When I first started playing tennis, I have a fam…