Burnley managed just three efforts on target at the Amex Stadium and their lack of threat in attack was compounded by errors at the back.
The absence of captain Josh Cullen, who is out for the season after suffering anterior cruciate ligament injury in the 0-0 draw against Everton on 27 December, was also sharply felt in a listless midfield display on a day when a despondent Parker could take few positives.
“What we need is what we had previous to today,” Parker added.
“While the results have not gone our way, we have been building on certain things and there has been a real commitment. We are going to lose matches but the way we lost today is not one which was nice and is not acceptable really. We need a reaction for sure.
“The saving grace is there is only x amount of points [six to safety] but that is irrelevant because if we perform like we did at times today, whatever the points are, we are not going to get enough [to stay up].”
Sweden international Hjalmar Ekdal echoed Parker’s sentiments when speaking to Sky Sports, adding: “I think today is worse than previous games.
“This game is not what we stand for or what we want to be defined by. As a team we were weak, not there, we have a lack of belief.
“I think we are all a bit embarrassed of ourselves. It is difficult to put it on one thing really, but just the mindset and the character of us all on the pitch. The duels and everything, how we fight and go through the game, we can all see that we are not really there and we are not really in the game.”