Gavin Gunning was left hugely frustrated after Swindon Town were once again let down by basic defensive errors in a 3-2 defeat to Mansfield Town.

Lucas Akins fired home after four minutes to give Mansfield the lead after a very lopsided first half.

That same pattern was not to be followed in a topsy-turvy second half as Paul Glatzel and Aaron Drinan both scored goals that levelled the game, but Davis Keillor-Dunn and Will Swan's strikes saw Town defeated.

Gunning said that he had worked all week with his defenders on marking in the box and they had still been caught out in those situations.

He said: "There were so many positives, but the realism is that when you conceded three goals that are horror shows like that then it is a frustrating afternoon.

"The first one is a decent but of play to get Keillor-Dunn into space, when we have worked all week on someone being goal-side of him and locking in on Nicholls, we don't lock in, he sets it around the corner and they have scored.

"Then you are chasing your tail and there were five minutes when it was like a tornado.

"Being an ex-defender, I only learned it when I was coming towards the end of my career that if you mark space in the box then you are going to concede goals.

"If you stand there and you think you are going to win the ball, you won't, if your body shape is closed and you are facing the ball then you are in big trouble because the ball is going over your head and if your mate doesn't tuck in and cover you are going to be in a tough position.

"I think Swan was six yards out and he has a free header, that is just having that desire to get close and feel contact in the box, we work on it all week.

"We literally work on in the box, don't mark space, get tight. That is it, simple.

"That is not how I want it done, so if they can't do it then they won't play."

The interim head coach also chose to revert to a back three for this game away from his preferred back four and he explained why that decision was made.

He said: "That was because we are coming to Mansfield and we have got to respect them.

"They are going to play two strikers that always stay high and outside each other.

"So, if you play a back four and don't lock in with the full-back then you are in big trouble.

"We had the two outside centre-halves lock in on the strikers and then the spare centre-half sweep round.

"I thought Zac played outstanding out high and wide and it was more lopsided with Dokes [Udoka Godwin-Malife] to come in off the shape to play and be powerful.

"Zac gave us good width and he was tearing the left-back apart, he didn't know if he was coming or going."