No one ever said 13-6 and 13-7 was "trying your best." Certain games you can tell whether not it was close just based on the gun play and general stuff like that. Sen vs FNC was a strategical outplay in most cases and didn't look like Sentinels gave it their all. A lot of rounds within that match up were given up by Sentinels such as Icebox. They were 5 rounds up and then threw 4 rounds in a row after that just with misplacement of economy and getting cocky with plays. Same thing happened on haven with their clear advantage after half and winning both pistol rounds.
Any 13-4 game is a massive strategical outplay and is in no way "trying your best." If anything, "being in the zone" would be the more accurate term since they were just "feeling it that day" and outplayed their opponents badly.
Sentinels so far looked far too dominant within the scene. My TSM flair has nothing to do with this particular analysis, since it's just the team I've supported since beta so your ad hominem is just irresponsible.