Star Wars: The Clone Wars - Season 5 Episode 8 -

With Ahsoka captured by Hondo, the younglings go to Florrum to rescue her, against the wishes of Obi-Wan Kenobi. However, before he can help the younglings, he is attacked by General Grievous and defeated, but nearly kills the droid general by setting the self-destruct on the Negotiator, after being defeated by Grievous in single-combat.