diff --git a/model/labels/regexp.go b/model/labels/regexp.go
index de4cfc3b1c..e6909dbeac 100644
--- a/model/labels/regexp.go
+++ b/model/labels/regexp.go
@@ -366,7 +366,7 @@ func optimizeAlternatingLiterals(s string) (StringMatcher, []string) {
 	// If there are no alternates, check if the string is a literal
 	if estimatedAlternates == 1 {
 		if regexp.QuoteMeta(s) == s {
-			return &equalStringMatcher{s: s, caseSensitive: true}, nil
+			return &equalStringMatcher{s: s, caseSensitive: true}, []string{s}
 		}
 		return nil, nil
 	}
diff --git a/model/labels/regexp_test.go b/model/labels/regexp_test.go
index f0e21b2d5c..a03bbd261d 100644
--- a/model/labels/regexp_test.go
+++ b/model/labels/regexp_test.go
@@ -342,6 +342,14 @@ func TestFindSetMatches(t *testing.T) {
 			matches, actualCaseSensitive := findSetMatches(parsed)
 			require.Equal(t, c.expMatches, matches)
 			require.Equal(t, c.expCaseSensitive, actualCaseSensitive)
+
+			if c.expCaseSensitive {
+				// When the regexp is case sensitive, we want to ensure that the
+				// set matches are maintained in the final matcher.
+				r, err := newFastRegexMatcherWithoutCache(c.pattern)
+				require.NoError(t, err)
+				require.Equal(t, c.expMatches, r.SetMatches())
+			}
 		})
 	}
 }
diff --git a/tsdb/querier_bench_test.go b/tsdb/querier_bench_test.go
index 501879d01b..60820eac0f 100644
--- a/tsdb/querier_bench_test.go
+++ b/tsdb/querier_bench_test.go
@@ -125,6 +125,7 @@ func benchmarkPostingsForMatchers(b *testing.B, ir IndexReader) {
 	iNotAlternate := labels.MustNewMatcher(labels.MatchNotRegexp, "i", "(1|2|3|4|5|6|20|55)")
 	iXYZ := labels.MustNewMatcher(labels.MatchRegexp, "i", "X|Y|Z")
 	iNotXYZ := labels.MustNewMatcher(labels.MatchNotRegexp, "i", "X|Y|Z")
+	literalRegexp := labels.MustNewMatcher(labels.MatchRegexp, "i_times_n", "0")
 	cases := []struct {
 		name     string
 		matchers []*labels.Matcher
@@ -168,6 +169,7 @@ func benchmarkPostingsForMatchers(b *testing.B, ir IndexReader) {
 		{`n="1",i=~".+",i!~"2.*",j="foo"`, []*labels.Matcher{n1, iPlus, iNot2Star, jFoo}},
 		{`n="1",i=~".+",i!~".*2.*",j="foo"`, []*labels.Matcher{n1, iPlus, iNotStar2Star, jFoo}},
 		{`n="X",i=~".+",i!~".*2.*",j="foo"`, []*labels.Matcher{nX, iPlus, iNotStar2Star, jFoo}},
+		{`i_times_n=~"0"`, []*labels.Matcher{literalRegexp}},
 	}
 
 	for _, c := range cases {