Serero is back to full fitness after a groin problem picked up towards the end of last campaign and says he is leaner to boot after hard work in the first few weeks of pre-season.
"Fortunately I can leave that behind me now," he says. "Thanks to various stability exercises I have been doing I have become a lot stronger than I was at this time last year.
"I'm stronger in the challenges and can better fend off opponents. Because I've become physically stronger, it allows me to play my natural game and my football has improved."
Serero had been dogged by weight issues in his first campaign, a symptom of his not being able to train because of injury. But he says he is over that too.
"Compared to eight months ago, I have made enormous strides. That gives me the motivation and confidence to continue working hard every time. "
There had been a suggestion that Serero might go out on loan this season, with his former Ajax Cape Town coach Foppe de Haan trying to persuade Heerenveen to take him on.
But Ajax coach Frank de Boer insists that the 22-year-old is in his plans for the coming campaign and has blocked any loan move.