The Moors were defeated due to an 81st minute goal by Ryan Bird at table toppers Dover Athletic, writes Tom Feaheny.
It was another case of Solihull dropping points when well placed going into the final stages of a game.
"We seem to have this habit of giving goals away, late on and it is costing us, I keep looking at the performance and being pleased, we just need to hold out teams," said McDonald to the club's website.
"It is such small margins we have lost again, this time to the team who are going top, we put in a performance as good as their's I feel for my players, I really do."
After this defeat they remain in the relegation places but McDonald is calling for calm.
"There is no need for any drastic changes, we look good and solid in defence, our midfield works hard, our attack shows a threat, we are so close to going on a good run, we just need to cut out mistakes."
"I honestly think we'll get something Tuesday, then we play a few sides who are near us, that should start a run of results."
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