2015 Western & Southern Open – Men's singles

Defending champion Roger Federer defeated Novak Djokovic in the final, 7–6, 6–3 to win the men's singles tennis title at the 2015 Cincinnati Masters. It was his seventh Cincinnati Masters title on his seventh final appearance, making him the second man to go undefeated in seven finals at the same Masters 1000 event (after Rafael Nadal at the Monte-Carlo Masters). For the second time in his career (after 2012), Federer did not lose a set or have his serve broken during the tournament. It marked the first time Federer defeated the world No. 1 and No. 2 players in consecutive matches en route to a title. It was Djokovic's fifth runner-up finish without winning the title; he would eventually do so in 2018.