William Byron wins first career NASCAR Xfinity Series race at Iowa William Byron won his first career NASCAR Xfinity Series race Saturday night at Iowajust one week after suffering a heartbreaking second-place finish to Denny Hamlin. The 19-year-old was a seven-time winner last year in the truck series and now sits third in the regular-season standings in addition to clinching a playoff spot. Read more http://www.cbssports.com/general/ne...st-career-nascar-xfinity-series-race-at-iowa/