Mansfield boss Nigel Clough was disappointed to see mistakes prove so costly after his side had played so well against Championship side Preston in a 3-0 Carabao Cup exit.
Scott Sinclair netted a brace and substitute Emil Riis added the other.
But Clough said: "I actually thought we played better than Saturday at times tonight – it was just that final ball.
"But I was bitterly disappointed with the first two goals we conceded as both were avoidable from double mistakes and that's what changed the game.
"You can't afford to give Championship sides with ex-Premier League players that sort of opportunity.
"Up until the second goal we were more than in it."
Stags were on top and wasted several chances until Sinclair neatly lobbed Nathan Bishop in first-half stoppage time.
Riis out-muscled Farrend Rawson on the left byline to make it 2-0 after 71 minutes before Ben Whiteman's cutting pass set up Sinclair for his second with nine minutes left.
Preston boss Frankie McAvoy said: "Mansfield are a good team and the pitch is a bit tight so we knew we'd be in for a tough game.
"But we managed to get the break just before half-time with a great pass from Sean (Maguire) who sliced Scottie (Sinclair) through for a fantastic finish which gave us a wee bit of breathing space at half-time.
"First half we needed to do better, but we were miles better in the second half.
"Second half we knew we needed that second goal as when you go to teams that are in lower divisions than yourself it is difficult. There are no easy games."
He added: "Once we got the second goal we showed a bit of class. We managed to retain the ball, move it, probe and the third goal was the icing on the cake."
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