Shiranui was with Liam during this time.  "Jen will likely use her Lucario," he stated, having lost to said Lucario, "The best Pokémon to use against it would be Fighting types that don't have a weakness to Ground-type moves.  Avoid Fire types because like what happened when I faced her, Aura will break out the Ground and/or Rock moves; and as tempting as it is to use a Ground type, Aura may know a move or two that would cover them."