It has been suggested that England have had the easier side of the draw than the likes of Les Bleus and the Red Devils, having faced the Swedes and Colombia in the knockout stages.
Mandzukic, though, has vowed that he and his compatriots will fight until the very last whistle against Gareth Southgate's men.
"Don't worry, I still have something in me for England," he said, after leading the line in the 2-2 draw with Russia.
"We will all fight until the end. And in that case, even if we lose, no one could blame us."
Croatia have never reached a World Cup final, their best finish coming in 1998, when they placed third, having lost to eventual winners France in the semis.
Mandzukic has been key to their run, scoring against Denmark in the last 16, and setting up a goal against Russia - both games, of course, ended by going to penalties.
And the Juventus striker believes he is improving with age.
"Where do I find strength? I really don't know. I remember some 'expert' ahead of World Cup saying this is not good old Mandzukic... Well, he was right, this is a new, even better Mandzukic!
"I always give my best for my club and my country."