The veteran prop had few answers after a disastrous 22-0 defeat at Huddersfield on Thursday.
Joint-bottom Castleford were a pale shadow of the side that had run riot against Wigan the week before and were dogged by errors.
They have not won at Huddersfield since 2009 but, more worryingly, the Challenge Cup finalists that almost finished top last term are in danger of becoming rooted in the bottom four.
“It was one of the worst performances we’ve put in for a long time,” admitted Lynch, whose side were just 6-0 down despite a horrendous first half.
“We got asked for a response at half-time and it just didn’t happen. The first set showed that when they just rolled us and overall it was very disappointing.
“(Coach) Daryl (Powell) asked us to do things and we didn’t react to his commands which is very disappointing as normally we’re pretty good at that.
“I can’t put a finger on it and a lot of people will be on our backs for this but it’s how we respond now. We can’t afford to go one from five as that is a really disappointing start and it’s a massive game versus Salford now.”
Lynch, who missed the Wigan win with a groin strain, conceded the defeat was a “massive setback” and added: “We had a game-plan to stick to but we turned over too much ball.
“Both sides did, to be fair, and it was probably a pretty dull game in that first half. I don’t think it got much better in the second, either. I bet a few people fell asleep.
“Super League is tight this year, though, and we want to win every game. I thought that was a crucial match we should have won.
“We’ve had to go through the horror show of doing the review and must put things right this Friday back at home.”