diff --git a/src/Core/GrpcTrait.php b/src/Core/GrpcTrait.php
index a3d28abf1332..355feeea0903 100644
--- a/src/Core/GrpcTrait.php
+++ b/src/Core/GrpcTrait.php
@@ -252,7 +252,7 @@ private function formatTimestampForApi($value)
         preg_match('/\.(\d{1,9})Z/', $value, $matches);
         $value = preg_replace('/\.(\d{1,9})Z/', '.000000Z', $value);
         $dt = \DateTimeImmutable::createFromFormat('Y-m-d\TH:i:s.u\Z', $value);
-        $nanos = (isset($matches[1])) ? $matches[1] : 0;
+        $nanos = (isset($matches[1])) ? str_pad($matches[1], 9, '0') : 0;
 
         return [
             'seconds' => (int)$dt->format('U'),
diff --git a/tests/unit/Core/GrpcTraitTest.php b/tests/unit/Core/GrpcTraitTest.php
index c95d5329ce9d..511e01232181 100644
--- a/tests/unit/Core/GrpcTraitTest.php
+++ b/tests/unit/Core/GrpcTraitTest.php
@@ -213,16 +213,44 @@ public function testFormatsList()
         $this->assertEquals($expected, $this->implementation->call('formatListForApi', [$list]));
     }
 
-    public function testFormatTimestampForApi()
+    /**
+     * @dataProvider timestampProvider
+     */
+    public function testFormatTimestampForApi($timestamp, $expectedSeconds, $expectedNanos)
+    {
+        $result = $this->implementation->call(
+            'formatTimestampForApi',
+            [$timestamp]
+        );
+
+        $this->assertEquals($expectedSeconds, $result['seconds']);
+        $this->assertEquals($expectedNanos, $result['nanos']);
+    }
+
+    public function timestampProvider()
     {
-        $seconds = '1491511965';
-        $nanos = '989898989';
-        $ts = '2017-04-06T20:52:45.'. $nanos .'Z';
-
-        $this->assertEquals([
-            'seconds' => $seconds,
-            'nanos' => $nanos
-        ], $this->implementation->call('formatTimestampForApi', [$ts]));
+        return [
+            [
+                '2017-08-24T00:38:30.611529Z',
+                '1503535110',
+                '611529000'
+            ],
+            [
+                '2017-08-24T00:38:30.000000000Z',
+                '1503535110',
+                '0'
+            ],
+            [
+                '2017-08-24T00:38:30.000000001Z',
+                '1503535110',
+                '1'
+            ],
+            [
+                '2017-04-06T20:52:45.989898989Z',
+                '1491511965',
+                '989898989'
+            ]
+        ];
     }
 
     /**