Crawley Town head coach Dermot Drummy pointed to defensive slips which led to them suffering their first league defeat of the season.
After a quiet first half, Reds took the lead two minutes into the restart through an individual effort by Enzio Boldewijn.
Notts County then responded with three goals to take three points through a James Collins own goal plus goals by Adam Campbell and Jon Stead from the penalty spot.
Drummy said: “Two of the goals could have been prevented and I thought if we took our chances could have nicked a point rather than deserved a point.
“I thought they were a very good side from upfront to midfield. At times we couldn’t get near them, probably because the legs in midfield were missing
“We’ve got to recover and go again on Tuesday against Colchester.
“It’s very important we stick together as a group - it is our first defeat, let’s not forget that.
“Today I thought that the attitude was fantastic. I didn;t think we had the power in us.
“We just have to regroup and take it on the chin. We gave two goals away we shouldn’t have given away today.
“We lost three points, that’s it, we have to stay positive, we now have a big game against Colchester and then we have a massive game at Portsmouth.”
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