Here is the team that played so well against Celtic.
Inverness CT: Fraser, Tokely, Dods, Munro, Hastings, Wilson, McBain, Duncan (Black 74), Rankin, Bayne, Wyness (McAllister 2), McAllister (Paatelainen 84). Subs Not Used: Ridgers, McCaffrey, Morgan, Soane.
Here is the team that played so poorly against Hearts.
Inverness CT: Fraser, Tokely, Dods, Munro, Hastings, Wilson (McSwegan 85), McBain, Duncan, Rankin (Morgan 63), Bayne, McAllister. Subs Not Used: Ridgers, McCaffrey, Black, Paatelainen, Soane.
Here is the team that played so (apparently) poorly against Motherwell.
Inverness CT: Fraser, Tokely, Dods, Munro, Hastings, Wilson, Duncan (Black 70), McBain, Rankin (Paatelainen 72), McAllister (McSwegan 75), Bayne.
So that's pretty much man for man the exact same team that played so well against Celtic yet has been so poor in the last couple of games.