Men's 100m Butterfly Semifinal 1
vendredi 30 juillet 2021, 01h30 GMT – 06h30 GMT
| Nom | Temps | |
|---|---|---|
| 1 |  Kristóf Milák | 50.31″ |
| 2 |  Josif Miladinov | + 0.75″ |
| 3 | Andrei Minakov | + 0.8″ |
| 4 |  Matthew Temple | + 0.81″ |
| 5 |  Mehdy Metella | + 1.01″ |
| 6 |  Naoki Mizunuma | + 1.15″ |
| 7 |  Jiajun Sun | + 1.51″ |
| 8 | Youssef Ramadan | + 1.96″ |