Bill Gates has warned that the fight against malaria could "go backwards" without innovation and long-term funding.
With mosquitoes adapting to drugs and insecticides, the philanthropist told the Malaria Summit London 2018: "We've got to get smarter."
The Microsoft co-founder said improved surveillance was vital to monitor mosquitoes and the parasites they carry.
Commonwealth leaders attending the event, co-hosted by the governments of Rwanda, Swaziland and the UK, have pledged to halve malaria across member countries within the next five years. This would prevent 350 million cases and save 650,000 lives.
Addressing the summit, Mr Gates said: "If we don't keep innovating, we will go backwards.
"If we don't maintain the commitments that we are making here today, malaria would go back and kill over a million children a year, because the drugs and the insecticides always are evaded by the mosquito and the parasite."
He added: "The funding has to be long-term, at these very substantial levels, and we've got to get smarter."
In 2016, for the first time in a decade, the number of malaria cases rose, according to the World Health Organisation (WHO).
There were an estimated 216 million cases, an increase of about five million from 2015. The number of deaths remained similar at 445,000.
Mr Gates said: "This set back, when the 2016 cases went up, that's a real signal to us.
"A real signal about tools, and about the richness of surveillance, and saying that let's step back and take this strategy into a new phase."
The Microsoft co-founder said data was the "lifeblood of how we are going to be smarter".
He said: "This surveillance has to be very detailed, not just in terms of location but fairly up-to-date.
"Waiting a year-and-a-half until you see what the burden is really doesn't let you respond in the way we want to."
He added: "We aren't completely there on this better surveillance, but we are making progress."
The UK Government has said it will spend £500 million a year on malaria over the next three years, while the Bill and Melinda Gates Foundation will extend its investments by an additional one billion US dollars (£700 million) until 2023.
Mr Gates recalled witnessing a boy affected by the disease have seizures during a visit to Tanzania.
He said: "The next five years we can do a lot, we can do as much or more than we've done even in the last 15 years.
"So this five years is a gateway to that long-term goal that no child would have to go through what I saw that child in Tanzania suffering from.
"It's very exciting and something we are incredibly committed to."
Malaria kills a child every two minutes and 90% of the Commonwealth population live in countries affected by the disease.