diff --git a/packages/vite/src/node/plugins/asset.ts b/packages/vite/src/node/plugins/asset.ts
index 74f0220a4e9c19..5954e1cd92fa2e 100644
--- a/packages/vite/src/node/plugins/asset.ts
+++ b/packages/vite/src/node/plugins/asset.ts
@@ -46,7 +46,7 @@ export const inlineRE = /[?&]inline\b/
 const assetCache = new WeakMap<Environment, Map<string, string>>()
 
 /** a set of referenceId for entry CSS assets for each environment */
-export const cssEntriesMap = new WeakMap<Environment, Set<string>>()
+export const cssEntriesMap = new WeakMap<Environment, Map<string, string>>()
 
 // add own dictionary entry by directly assigning mrmime
 export function registerCustomMime(): void {
@@ -148,7 +148,7 @@ export function assetPlugin(config: ResolvedConfig): Plugin {
 
     buildStart() {
       assetCache.set(this.environment, new Map())
-      cssEntriesMap.set(this.environment, new Set())
+      cssEntriesMap.set(this.environment, new Map())
     },
 
     resolveId: {
diff --git a/packages/vite/src/node/plugins/css.ts b/packages/vite/src/node/plugins/css.ts
index daac55989b4429..fff6ae63d9731a 100644
--- a/packages/vite/src/node/plugins/css.ts
+++ b/packages/vite/src/node/plugins/css.ts
@@ -863,7 +863,7 @@ export function cssPostPlugin(config: ResolvedConfig): Plugin {
               source: chunkCSS,
             })
             if (isEntry) {
-              cssEntriesMap.get(this.environment)!.add(referenceId)
+              cssEntriesMap.get(this.environment)!.set(chunk.name, referenceId)
             }
             chunk.viteMetadata!.importedCss.add(this.getFileName(referenceId))
           } else if (this.environment.config.consumer === 'client') {
diff --git a/packages/vite/src/node/plugins/manifest.ts b/packages/vite/src/node/plugins/manifest.ts
index 064e20d2142818..1b94bd7f28e619 100644
--- a/packages/vite/src/node/plugins/manifest.ts
+++ b/packages/vite/src/node/plugins/manifest.ts
@@ -21,7 +21,7 @@ export interface ManifestChunk {
   assets?: string[]
   isEntry?: boolean
   name?: string
-  names?: string[]
+  // names field is deprecated (removed from types, but still emitted for backward compatibility)
   isDynamicEntry?: boolean
   imports?: string[]
   dynamicImports?: string[]
@@ -122,25 +122,27 @@ export function manifestPlugin(): Plugin {
       function createAsset(
         asset: OutputAsset,
         src: string,
-        isEntry?: boolean,
+        name?: string,
       ): ManifestChunk {
         const manifestChunk: ManifestChunk = {
           file: asset.fileName,
           src,
         }
-        if (isEntry) {
+        if (name) {
           manifestChunk.isEntry = true
+          manifestChunk.name = name
+          // @ts-expect-error keep names field for backward compatibility
           manifestChunk.names = asset.names
         }
         return manifestChunk
       }
 
       const entryCssReferenceIds = cssEntriesMap.get(this.environment)!
-      const entryCssAssetFileNames = new Set()
-      for (const id of entryCssReferenceIds) {
+      const entryCssAssetFileNames = new Map<string, string>()
+      for (const [name, id] of entryCssReferenceIds) {
         try {
           const fileName = this.getFileName(id)
-          entryCssAssetFileNames.add(fileName)
+          entryCssAssetFileNames.set(fileName, name)
         } catch {
           // The asset was generated as part of a different output option.
           // It was already handled during the previous run of this plugin.
@@ -157,8 +159,8 @@ export function manifestPlugin(): Plugin {
             chunk.originalFileNames.length > 0
               ? chunk.originalFileNames[0]
               : `_${path.basename(chunk.fileName)}`
-          const isEntry = entryCssAssetFileNames.has(chunk.fileName)
-          const asset = createAsset(chunk, src, isEntry)
+          const name = entryCssAssetFileNames.get(chunk.fileName)
+          const asset = createAsset(chunk, src, name)
 
           // If JS chunk and asset chunk are both generated from the same source file,
           // prioritize JS chunk as it contains more information
diff --git a/playground/backend-integration/__tests__/backend-integration.spec.ts b/playground/backend-integration/__tests__/backend-integration.spec.ts
index 5a314d6b9d5a76..e0aeef00d1a793 100644
--- a/playground/backend-integration/__tests__/backend-integration.spec.ts
+++ b/playground/backend-integration/__tests__/backend-integration.spec.ts
@@ -54,6 +54,7 @@ describe.runIf(isBuild)('build', () => {
     const scssAssetEntry = manifest['nested/blue.scss']
     const imgAssetEntry = manifest['../images/logo.png']
     const dirFooAssetEntry = manifest['../../dir/foo.css']
+    const customNameAssetEntry = manifest['../../dir/custom.css']
     const iconEntrypointEntry = manifest['icon.png']
     const waterContainerEntry = manifest['water-container.svg']
     expect(htmlEntry.css.length).toEqual(1)
@@ -74,7 +75,8 @@ describe.runIf(isBuild)('build', () => {
     expect(dirFooAssetEntry).not.toBeUndefined() // '\\' should not be used even on windows
     // use the entry name
     expect(dirFooAssetEntry.file).toMatch('assets/bar-')
-    expect(dirFooAssetEntry.names).toStrictEqual(['bar.css'])
+    expect(dirFooAssetEntry.name).toStrictEqual('bar.css')
+    expect(customNameAssetEntry.name).toStrictEqual('bar.custom')
     expect(iconEntrypointEntry?.file).not.toBeUndefined()
     expect(waterContainerEntry?.file).not.toBeUndefined()
   })
diff --git a/playground/backend-integration/dir/custom.css b/playground/backend-integration/dir/custom.css
new file mode 100644
index 00000000000000..086058a71f67e2
--- /dev/null
+++ b/playground/backend-integration/dir/custom.css
@@ -0,0 +1,3 @@
+.custom {
+  color: red;
+}
diff --git a/playground/backend-integration/vite.config.js b/playground/backend-integration/vite.config.js
index f432f139a4f6d9..7560c31541ac22 100644
--- a/playground/backend-integration/vite.config.js
+++ b/playground/backend-integration/vite.config.js
@@ -23,6 +23,10 @@ function BackendIntegrationExample() {
 
       entrypoints.push(['tailwindcss-colors', 'tailwindcss/colors.js'])
       entrypoints.push(['bar.css', path.resolve(__dirname, './dir/foo.css')])
+      entrypoints.push([
+        'bar.custom',
+        path.resolve(__dirname, './dir/custom.css'),
+      ])
 
       return {
         server: {