diff --git a/CHANGELOG.md b/CHANGELOG.md
index ffa6f15..00006f6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,7 +2,7 @@
 
 ## 3.0.1 under development
 
-- no changes in this release.
+- Enh #131: Throw `InvalidArgumentException` when missed "one" plural key (@vjik) 
 
 ## 3.0.0 February 17, 2023
 
diff --git a/composer.json b/composer.json
index bd0616a..49060bb 100644
--- a/composer.json
+++ b/composer.json
@@ -25,7 +25,7 @@
     },
     "require-dev": {
         "maglnet/composer-require-checker": "^4.2",
-        "phpunit/phpunit": "^9.5",
+        "phpunit/phpunit": "^9.6",
         "rector/rector": "^1.0.0",
         "roave/infection-static-analysis-plugin": "^1.25",
         "spatie/phpunit-watcher": "^1.23",
diff --git a/src/SimpleMessageFormatter.php b/src/SimpleMessageFormatter.php
index 36d1d93..e6f5538 100644
--- a/src/SimpleMessageFormatter.php
+++ b/src/SimpleMessageFormatter.php
@@ -83,7 +83,11 @@ private static function pluralize(mixed $value, string $options): string
             $map[$match] = $pluralMatches[3][$index];
         }
 
-        if (!in_array(self::PLURAL_OTHER, $pluralMatches[1], true)) {
+        if (!isset($map[self::PLURAL_ONE])) {
+            throw new InvalidArgumentException('Missing plural key "' . self::PLURAL_ONE . '".');
+        }
+
+        if (!isset($map[self::PLURAL_OTHER])) {
             throw new InvalidArgumentException('Missing plural key "' . self::PLURAL_OTHER . '".');
         }
 
diff --git a/tests/SimpleMessageFormatterTest.php b/tests/SimpleMessageFormatterTest.php
index 6a8bd70..f43d076 100644
--- a/tests/SimpleMessageFormatterTest.php
+++ b/tests/SimpleMessageFormatterTest.php
@@ -100,7 +100,7 @@ public function testFormatPluralWithNonInteger(): void
         $formatter->format('{min, plural, one{character} other{characters}}', ['min' => 'str']);
     }
 
-    public function testFormatPluralWithMissingKey(): void
+    public function testFormatPluralWithMissingOtherKey(): void
     {
         $formatter = new SimpleMessageFormatter();
 
@@ -109,6 +109,15 @@ public function testFormatPluralWithMissingKey(): void
         $formatter->format('{min, plural, one{character}}', ['min' => 1]);
     }
 
+    public function testFormatPluralWithMissingOneKey(): void
+    {
+        $formatter = new SimpleMessageFormatter();
+
+        $this->expectException(InvalidArgumentException::class);
+        $this->expectExceptionMessage('Missing plural key "one".');
+        $formatter->format('{min, plural, other{characters}}', ['min' => 1]);
+    }
+
     public function dataFormatPluralWithMissingKeys(): array
     {
         return [