diff --git a/lib/protoparser/opentsdb/parser.go b/lib/protoparser/opentsdb/parser.go
index a63ccda30..7f8a43f8e 100644
--- a/lib/protoparser/opentsdb/parser.go
+++ b/lib/protoparser/opentsdb/parser.go
@@ -84,20 +84,24 @@ func (r *Row) unmarshal(s string, tagsPool []Tag) ([]Tag, error) {
 	tail = trimLeadingSpaces(tail[n+1:])
 	n = strings.IndexByte(tail, ' ')
 	if n < 0 {
-		return tagsPool, fmt.Errorf("cannot find whitespace between value and the first tag in %q", s)
+		// see https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3290
+		n = len(tail)
 	}
 	v, err := fastfloat.Parse(tail[:n])
 	if err != nil {
 		return tagsPool, fmt.Errorf("cannot parse value from %q: %w", tail[:n], err)
 	}
 	r.Value = v
-	tagsStart := len(tagsPool)
-	tagsPool, err = unmarshalTags(tagsPool, tail[n+1:])
-	if err != nil {
-		return tagsPool, fmt.Errorf("cannot unmarshal tags in %q: %w", s, err)
+	if len(tail) > n {
+		tagsStart := len(tagsPool)
+		tagsPool, err = unmarshalTags(tagsPool, tail[n+1:])
+		if err != nil {
+			return tagsPool, fmt.Errorf("cannot unmarshal tags in %q: %w", s, err)
+		}
+		tags := tagsPool[tagsStart:]
+		r.Tags = tags[:len(tags):len(tags)]
 	}
-	tags := tagsPool[tagsStart:]
-	r.Tags = tags[:len(tags):len(tags)]
+
 	return tagsPool, nil
 }
 
diff --git a/lib/protoparser/opentsdb/parser_test.go b/lib/protoparser/opentsdb/parser_test.go
index d2e739f90..7e7c435c9 100644
--- a/lib/protoparser/opentsdb/parser_test.go
+++ b/lib/protoparser/opentsdb/parser_test.go
@@ -37,9 +37,6 @@ func TestRowsUnmarshalFailure(t *testing.T) {
 	f("put aaa timestamp")
 	f("put foobar 3df4 -123456 a=b")
 
-	// Missing first tag
-	f("put aaa 123 43")
-
 	// Invalid value
 	f("put aaa 123 invalid-value")
 	f("put foobar 789 -123foo456 a=b")
@@ -104,6 +101,14 @@ func TestRowsUnmarshalSuccess(t *testing.T) {
 			},
 		}},
 	})
+	// No tags
+	f("put foobar 789 -123.456", &Rows{
+		Rows: []Row{{
+			Metric:    "foobar",
+			Value:     -123.456,
+			Timestamp: 789,
+		}},
+	})
 	// Fractional timestamp that is supported by Akumuli.
 	f("put foobar 789.4 -123.456 a=b", &Rows{
 		Rows: []Row{{