Manager Richie Barker admitted Crawley could have pulled off another famous win at Bramall Lane if they had been more clinical.
Jamie Proctor gave Reds an early lead but Mat Sadler and Proctor were unable to take good opportunities to hammer home their dominance in the first half.
Those misses proved costly as Sheffield United staged a comeback in the second half with Marlon King grabbing a 63rd minute equaliser.
Barker said: "After our first half performance we deserved to come in more than one goal up. If we had got gone two or three up in the game then it would have been a different second half.
"No two halfs of football are ever the same and those two were certainly different. As well as we played in the first half we had to dig in in the second half but I thought the boys were fantastic.
"They were gutted in the changing room afterwards but the fact we have come to a place like Sheffield United and are disappointed with a point tells its own story."
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