"unrivalled influence" is correct and usable in written English.
You could use this phrase to describe something that has a strong, unparalleled impact. For example: "The new president's unrivalled influence has greatly changed the landscape of the country."
After the Cold War, the U.S. enjoyed a period of almost unrivalled influence, free to intervene more or less wherever it wanted.
Rafsanjani's standing and political acumen not only helped give him unrivalled influence over the course of politics (including Khamenei's succession as leader in 1989) but led many, on both left and right, to resent his alleged opportunism.
With Lady Marlborough's advancements as Groom of the Stole, Mistress of the Robes, and Keeper of the Privy Purse, the Marlboroughs, now at the height of their powers with the Queen, enjoyed a joint annual income of over £60,000, and unrivalled influence at court.
First, even when Rome was the master of the world, Homer and the Greeks were unrivalled in the influence they exercised among the educated class.
It has allowed America to multiply its influence through an unrivalled network of alliances.
Tamasin Cave, of the Alliance for Lobbying Transparency, said: "This proves what's long been understood, which is that the pharmaceuticals industry is a formidable lobbyist with unrivalled access to policy-makers and significant influence".
Today as the chief port in a country that has one of Asia's fastest growing economies, and as the nucleus of Philippine commerce, banking, media, tourism, legal services, fashion and the arts, Manila's influence upon domestic affairs is unrivalled.
As a source of inspiration and influence on his profession, he was unrivalled by any actor in his time except for Laurence Olivier.
As a source of inspiration and influence upon his profession he was unrivalled by any actor in his time except for Laurence Olivier.
The influence of ADE on The Netherlands and its fertile electronic music industry is unrivalled.
Jones's earliest work as an engraver shows Gill's influence, as do the lettered inscriptions, at once poetry and visual art, in which he was unrivalled.
