Derby boss Paul Jewell was left to rue the Rams' luck after Sunderland denied his new side a valuable point with a last-gasp winner.
Substitute Anthony Stokes netted the last minute strike to make it 1-0 in the Stadium of Light and break the Rams' hearts.
A disappointed Jewell, who took over rock-bottom Derby earlier in the week, said Sunderland had only had two chances in the game.
"It is a kick in the teeth for us," he admitted, but believed his players will show more improvement in the days to come, given they have only had two training sessions together.
Asked about his first impression of the team he has inherited, he said: "There are some good players - obviously they are low on confidence and that is what happens when you are bottom of the league.
"When you haven't scored a goal away from home, all these things play on your mind. And that is what we will try and change.
"It is not easy to change - it certainly won't change overnight. But I have seen enough signs there today, the endeavour is certainly there," he said, although he admitted his team lack "a little bit of a cutting edge at times".
But overall, he was pleased with what his players gave him.
He said: "We know we are up against it but the lads gave me everything they had today.
"As far as endeavour and effort are concerned I can't be critical."
While he was disappointed in the goal Derby conceded, he did not think his team had crumbled.
"That's their only chance of the second half I think.
"We've hit the post, they've hit the post. Other than that it wasn't a particularly great game," he said, adding: "It would have been a nice point for us to walk away with. It wasn't to be. So we have to pick ourselves up and dust ourselves down."
Jewell is relishing having more time to prepare his players before their next game than he had for this.
"This week will give me a full week to try and get to know who can do what and what strengths and weaknesses we have," he said.