2023 Western & Southern Open – Men's singles

Novak Djokovic defeated Carlos Alcaraz in the final, 5–7, 7–6^(9–7), 7–6^(7–4) to win the men's singles tennis title at the 2023 Cincinnati Masters. He saved a championship point en route to his third Cincinnati Masters title and record-extending 39th ATP Tour Masters 1000 title overall; it was his ninth career title won after saving match points during a tournament, and his second time of the year, after Adelaide. At 3 hours and 49 minutes, this match was the longest best-of-three-sets ATP Tour final and the longest match in the tournament's history. The final was named the ATP's Match of the Year.

Borna Ćorić was the defending champion, but lost in the second round to Hubert Hurkacz.

Alcaraz and Djokovic were in contention for the ATP No. 1 singles ranking. Alcaraz retained the top ranking by reaching the final. This was Djokovic's first tournament in the United States since the 2021 US Open, following the lifting of COVID-19 vaccination requirements for international air travelers in May 2023.