Mark Molesley called for his side to start standing up after Weymouth suffered a 2-1 loss at Merthyr Town in the Evo-Stik Southern Premier South.
Goals from Ian Traylor and Owain Jones condemned the Terras to defeat, despite Ben Thomson scoring in the 90th minute.
When asked where he thought it went wrong, Molesley said: “Unfortunately we got punished by two mistakes. We got caught in possession in good areas and got punished.
“Unfortunately that seems to be the theme of our season at the moment, we are getting undone by some basic errors, getting punished and it shows – it is a brutal league.
“We have got to start standing up, we have got to stop making basic errors and be better in both boxes.”
Molesley also conceded his side are not favourites for the league title now, with his side unable to reclaim the top spot via games in hand.
The Terras currently sit third but will slip to fourth should the Met Police earn a point in their game in hand.
Molesley said: “It is a disappointing time for us at the moment, we have let a few leads slip.
“We have got a lot to work on. We fully are chasing now.
“I don’t think we will be favourites for the league now and it is up to us to earn our respect back.”
Weymouth FC / Dorset Echo