Sherwood had made nine changes to his team for the second round tie which Villa needed extra-time to prevail after it ended 3-3 in normal time.
"But then they needed the game time. I thought we had enough on the pitch to win but you have to give a lot of credit to Notts County, who conducted themselves very well and came to play football.
"To be honest with you we would not be that open in a Premier League game. The reason that those players were picked is because they needed games and the minutes on the field, although they probably got too many minutes what with the extra time."
Villa were served by a hat-trick from Scott Sinclair plus goals from Adama Traore (first for the club) and Joe Bennett while County had Genaro Snijder, Jon Stead and former Villa young gun Graham Burke for their goals.