Manager Steve Evans felt Crawley's performance in the 3-0 defeat at promotion rivals Swindon was their worst for 18 months.
Swindon moved above the Red Devils into fourth spot and the hosts might have scored more goals near the end as reserve goalkeeper Michel Kuipers saved from Matt Ritchie.
"We were second best and were well beaten. This was the worst we have played in 18 months," said Evans. "We were never on the front foot and that is most unlike us.
"There were other factors, not least the way Swindon's players crowded the referee at every decision.
"In fairness Swindon have got a good side, good players and a good manager. They also worked their system very well.
"Overall I can have no complaints about the result, only with the way we played."