Marcelo Brozovic, Ivan Perisic, Ivica Olic, Gordon Schildenfeld and Danijel Pranjic all got on the score sheet as Croatia sealed a 5-1 triumph to maintain their unbeaten run and top spot in Group H.
However, Kovac was disappointed with his side's performance in the opening half, suggesting that they underestimated the quality of the opposition.
"We can be satisfied with victory and points gained, but I can't be satisfied with the first half, especially the first half an hour," said Kovac.
"Norway created too many problems for us, and we were not aggressive enough, not strong enough in duels, and we played too individually – I thought they were on the brink of scoring."
Despite the Norway pressure, it was the hosts who went ahead when, after 30 minutes, Brozovic fired home from 20 yards out.
In-form Perisic then added a second shortly after the interval – his fourth goal in as many qualifiers – before Olic tapped home after being teed up by Mario Mandzukic.
Tarik Elyounoussi missed a penalty for Norway after being fouled by Vedran Corluka – who received his marching orders soon after for a second bookable offence.
Alexander Tettey pulled a goal back for Norway with 10 minutes remaining, but late strikes from substitute Schildenfeld and Pranjic quelled any lingering hope for Per-Mathias Hogmo's side.
"Brozovic's opener helped us to show our quality and I told the players that we have to do better in the second half, and we did", added Kovac.
"Everything can be settled in the first half an hour. OK, I am satisfied with the score, but we can lose to stronger opponents than Norway at the very beginning.
"We are not in France yet and we have to put in a better performance against Italy in June in Zagreb".
