But the eastern Europeans, two-time Olympic gold medallists, made their move by throwing in five unanswered efforts in the run-up to half-time to take a 14-9 lead at the break.
Denmark, who won the European Championship in January, were not at their best and five of the first six goals after the break saw Croatia's advantage stretch to 19-10.
That become a 12-goal lead for Croatia with 10 minutes to go as Slavko Goluza's side really laid down a marker to the rest of the competition.
The Scandinavians had no answer, and although they did close the gap by one, Croatia saw it out with ease to put themselves in pole position to finish top of the group and earn a favourable quarter-final tie.
Domagoj Duvnjak, Igor Vori and Zlatko Horvat each threw in five goals, a tally matched by two Danes as the afternoon session was brought to a close.