Mandzukic retired from international duty following his country's run to the World Cup final and Croatia have scored just one goal in three matches since, the latest of which was a 0-0 draw against England on Friday.
That result followed a 6-0 drubbing at the hands of Spain but coach Dalic is focusing on the future, rather than dwelling on the past.
"It is not like us not to be able to score two matches in a row," he said. "But we have to forget Mandzukic, it is over, he is not with us anymore.
"He made his decision and we have to respect that and look for other solutions."
Croatia rode their luck at times in a match that was played behind closed doors as punishment for a swastika that was marked on the pitch ahead of a Euro 2016 qualifier against Italy.
England hit the woodwork twice through Eric Dier and Harry Kane, while Marcus Rashford squandered two golden opportunities in the second half.
"It was a tough game, as we expected. We were compact and aggressive, better than in last match," said Dalic.
"It was not easy to come back after such a big defeat. It is still not as we should be playing, we have to be braver in attack, more decisive and keep the ball better.
"We created some good chances but also were lucky with them hitting woodwork twice. I am satisfied with our game organisation and defensive block, which was bad in Spain.
"It was not easy to play that kind of game [at an empty stadium], it was sad and I hope it's the last time. I hope we will host Spain in front of 30,000 people in Maksimir Stadium.
"I am satisfied with our performance, although I hope we'll be better."