The U.S. Republican has, since his shock election victory in November over Democrat Hillary Clinton, called into question the "One China" policy that Washington has adhered to for decades.
His pick for secretary of state, former Exxon Mobil CEO Rex Tillerson, also told a confirmation hearing that Beijing's militarisation of reclaimed islands in the disputed waters of the South China Sea must be stopped.
That is music to the ears of the foreign policy establishment in New Delhi, as are Trump's tentative - albeit in Washington controversial - overtures towards Russia's President Vladimir Putin, whom Modi on Tuesday called "an abiding friend".
Modi was addressing the second annual Raisina Dialogue, a geopolitical gathering in New Delhi sponsored by India's foreign ministry and the Observer Research Foundation, a think tank, that is competing for attention with the higher-profile World Economic Forum in Davos, Switzerland.
Speaking in Davos, Chinese President Xi Jinping avoided mention of Trump and instead mounted a vigorous defence of free trade that the American president-elect has vowed to roll back to protect U.S. jobs.
Although many of the guests in New Delhi were former, rather than current prime ministers, they did include the top U.S. naval commander in the Pacific, Admiral Harry Harris.
Modi, elected on a nationalist platform in 2014, called for a rules-based security architecture in the Asia-Pacific that is "open, transparent, balanced and inclusive, and promote(s) dialogue and predictable behaviour rooted in international norms and respect for sovereignty."
That reflects not only India's concerns about the South China Sea, but fears that Beijing is threading a "string of pearls" in the Indian Ocean theatre by building strategic ports in countries like Sri Lanka, Pakistan and Djibouti on the eastern coast of Africa.
India has maritime interests in all directions that are "strategic and significant", said Modi, whose country is the world's fourth-largest oil importer and juts southward from the Eurasian landmass into the strategic shipping lane running from the Middle East to the rising economies of the Asia-Pacific.
"Primary responsibility for security in the Indian Ocean rests with those who live in this region," he said.
"Respecting freedom of navigation and adhering to international norms are essential for peace and growth in the larger and interlinked marine geography of the Indo-Pacific."