diff --git a/packages/tailwindcss-language-service/src/completionProvider.ts b/packages/tailwindcss-language-service/src/completionProvider.ts
index 6aa6d24f3d50ad353acf2173cb140d53484f1cf9..825a2e334412bea16ebd4e5e37b1b5a087005d55 100644
--- a/packages/tailwindcss-language-service/src/completionProvider.ts
+++ b/packages/tailwindcss-language-service/src/completionProvider.ts
@@ -197,62 +197,6 @@
   return null
 }
 
-function createMultiRegexp(regexString: string) {
-  let insideCharClass = false
-  let captureGroupIndex = -1
-
-  for (let i = 0; i < regexString.length; i++) {
-    if (
-      !insideCharClass &&
-      regexString[i] === '[' &&
-      regexString[i - 1] !== '\\'
-    ) {
-      insideCharClass = true
-    } else if (
-      insideCharClass &&
-      regexString[i] === ']' &&
-      regexString[i - 1] !== '\\'
-    ) {
-      insideCharClass = false
-    } else if (
-      !insideCharClass &&
-      regexString[i] === '(' &&
-      regexString.substr(i + 1, 2) !== '?:'
-    ) {
-      captureGroupIndex = i
-      break
-    }
-  }
-
-  const re = /(?:[^\\]|^)\(\?:/g
-  let match: RegExpExecArray
-  let nonCaptureGroupIndexes: number[] = []
-
-  while ((match = re.exec(regexString)) !== null) {
-    if (match[0].startsWith('(')) {
-      nonCaptureGroupIndexes.push(match.index)
-    } else {
-      nonCaptureGroupIndexes.push(match.index + 1)
-    }
-  }
-
-  const regex = new MultiRegexp(
-    new RegExp(
-      regexString.replace(re, (m) => m.substr(0, m.length - 2)),
-      'g'
-    )
-  )
-
-  let groupIndex =
-    1 + nonCaptureGroupIndexes.filter((i) => i < captureGroupIndex).length
-
-  return {
-    exec: (str: string) => {
-      return regex.execForGroup(str, groupIndex)
-    },
-  }
-}
-
 async function provideCustomClassNameCompletions(
   state: State,
   document: TextDocument,
@@ -277,10 +221,10 @@       let [containerRegex, classRegex] = Array.isArray(regexes[i])
         ? regexes[i]
         : [regexes[i]]
 
-      containerRegex = createMultiRegexp(containerRegex)
+      containerRegex = new MultiRegexp(new RegExp(containerRegex, 'g'))
       let containerMatch
 
-      while ((containerMatch = containerRegex.exec(str)) !== null) {
+      while ((containerMatch = containerRegex.execForGroup(str, 1)) !== null) {
         const searchStart = document.offsetAt(searchRange.start)
         const matchStart = searchStart + containerMatch.start
         const matchEnd = searchStart + containerMatch.end
@@ -289,11 +233,14 @@         if (cursor >= matchStart && cursor <= matchEnd) {
           let classList
 
           if (classRegex) {
-            classRegex = createMultiRegexp(classRegex)
+            classRegex = new MultiRegexp(new RegExp(classRegex, 'g'))
             let classMatch
 
             while (
-              (classMatch = classRegex.exec(containerMatch.match)) !== null
+              (classMatch = classRegex.execForGroup(
+                containerMatch.match,
+                1
+              )) !== null
             ) {
               const classMatchStart = matchStart + classMatch.start
               const classMatchEnd = matchStart + classMatch.end