I dont think thats fair.
The only big game I dont think we turned up in was the League Cup semi-final, and even that game was down to "moments".
Performance wise, we have been excellent against Hearts twice, Celtic three times and Rangers three times.
Results wise you could make an argument for it, but given all 3 teams have significantly bigger budgets than us and are above us in the league, they might just be better/luckier than us.
The fact that we have been able to go toe to toe with them is a significant improvement on mindset and performance levels from years gone past.
Of course, if we want to develop and get better, Jens will have to find a way to bridge the gap and turn those performances into results.