Gary Thornton wants a ‘marked improvement’ from his side after the disappointing defeat at local rivals York City Knights on Good Friday.
The 16-8 reverse saw Doncaster drop to seventh place in the early League One standings.
It came on the back of a thumping defeat to promotion favourites Toronto Wolfpack last time out.
Thornton said: “I don’t think you can fault our effort, we gave it everything but just came up short on certain things so that’s very disappointing.
“We weren’t clinical enough today and that’s been the story of the season so far, we’ve got to take our chances when they come in games.
“We’ve got a couple of weeks until our next league game now and we’ll be working on areas we can get better at between now and then so hopefully we will see a marked improvement.”
The Dons led by two points at half time at Bootham Crescent thanks to a Feka Paleaaesina try.
But they were unable to see the game out and afterwards Thornton admitted his side got the basics wrong and that the performance was well below par.
“We didn’t get going in attack, we were nowhere near creative enough and relied on our middles to get us going,” he said.
“It’s impossible to win games of rugby league if you’re not creating clear chances and that’s where we’ve gone wrong today.
“We weren’t too bad defensively, we limited the amount of points they scored but switched off at key times and you can’t afford to do that at any level.”
The Dons travel to Super League giants Leeds Rhinos on Friday in the Challenge Cup.