Cardiff recorded their first win against Leinster since January 2022, with scrum-half Aled Davies scoring the decisive try. The hosts led 3-0 at halftime through Callum Sheedy's penalty before extending their advantage in the 54th minute.
Leinster responded with a converted try by Luke McGrath in the 68th minute but couldn't find another score despite Cardiff being reduced to 14 men. The victory lifts Cardiff to third in the table, level on points with second-placed Leinster and with a 15-point advantage over teams chasing play-off spots.