Dublin boss Ger Brennan was left to rue a poor opening half in their Allianz League Division 1 loss to Donegal but praised how his players fought back in the second period.
Beaten All-Ireland finalists Donegal led by six points, 1-09 to 0-06, at half time, but the hosts at Croke Park narrowed the margin back to three at the final whistle.
Brennan, who took charge of the Dubs last August, admitted that the Ulster side deserved their victory.
"A game of two halves," the former Dublin defender, who handed league debuts to four starters and a substitute, told RTÉ Sport after the 1-20 to 0-20 loss.
"I guess the first half we lacked a lot of energy, we stood off Donegal. They played the game on their terms and credit to them.
"They were excellent at what they did.
"They cut us open on numerous occasions and we really couldn't get our hands on the ball.
"I think we gave the ball away seven times in a row during that first half and that just gave the impetus to Donegal.
"They're very accurate in front of the posts.
"There was a quick chat at half-time there with the group, maybe the few nerves that may have been there, I think they were gone and the fellas knew that there was a lot more in them.
"So delighted in how the guys did in the second half.
"They learned, they pushed on and we got it back to a goal.
"But having only played for 35 minutes to be within three points, against the All-Ireland finalists, happy but things to work on.
"If we performed in the second half with a similar energy to the first, you'd be quite worried.
"There'd be bigger problems there to probably try to unearth.
"We might have to get a couple of psychologists in if that was the case.
"But thankfully, we can see when the lads are tuned in and they back themselves that they can be quite competitive with the best."
Dublin face Mayo next weekend.
Brennan added: "Donegal are the standard along with Kerry and a couple of other teams that Dublin are trying to close the gap on.
"We'll just have to try and start better now in Castlebar next weekend."
Meanwhile, Donegal manager Jim McGuinness (above), who had just seven of the team that lost to Kerry in the All-Ireland final, said it was a mixed performance from his charges.
"It was good and bad," said McGuinness, whose side host Kerry next Sunday.
"There was a lot of positives - any day you come to Dublin and you win it's a good day, I suppose, but we've a lot of tidying up to do as well.
"Dublin were very good in the second half on their own kick-out They overloaded their strong side and got a lot of bodies in that area and asked a lot of questions of us.
"They went very direct in the second half and their scoring efficiency was very high. We were struggling to stem the tide.
"Overall, I think it's the first 70 minutes for a lot of the lads.
"You are kind of managing minutes throughout the pre-season and trying to give everyone a go at it and that's probably a good blast for them tonight."
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