The Danes face Zlatko Dalic's side in Nizhny Novgorod on July 1st for a spot in the quarter-finals.
"It will be absolutely different against Croatia, we will attack," Hareide told reporters at the team's Black Sea coast training base in Anapa.
Some fans in Moscow expressed their frustration by booing at the final whistle after the first 0-0 of the tournament on Tuesday -- a result which saw France top Group C and Denmark progress as runners-up.
Even the official FIFA World Cup Twitter account hinted at boredom: "Lots of huffing and puffing, but..... Both sides progress to round of 16."
But the 64-year-old Hareide said "only the result" mattered for Denmark who were happy to save energy for the next round.
"It's not the first time you've seen this in World Cup football and not the first time teams have been criticised for doing nothing," he said.
"We wanted to do it ourselves because we couldn't trust Peru to beat Australia."
The draw meant Denmark advanced to the latter stages of a World Cup for the time since 2002, while extending their impressive unbeaten run to 18 matches.
"It's difficult to make everyone happy," said defender Mathias Jørgensen.
"It's not like we play like that every game, so for us (Monday) didn't really matter for us. The most important thing was to get the result."
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