Sir Alex Ferguson believes his Manchester United side were fortunate to claim FA Cup victory at the expense of Blue Square Bet Premier outfit Chorley.
Stand-in skipper Wes Brown sent United through with a first-half header, but Crawley came on strong in the second half and hit the crossbar through Richard Brodie in stoppage time.
"They deserved a draw given their second-half performance," he said.
"There is no doubt a few players did not do themselves justice.
"I had no complaints in the first half, I thought we did okay - but we weren't at the races in the second. We were second to every ball.
"It was disappointing. We had some players who maybe don't understand what FA Cup football is like. For them, that is the biggest lesson."