diff --git a/backup/moodle2/restore_stepslib.php b/backup/moodle2/restore_stepslib.php
index 6178a04c790..2f9ada8b08c 100644
--- a/backup/moodle2/restore_stepslib.php
+++ b/backup/moodle2/restore_stepslib.php
@@ -2827,8 +2827,7 @@ abstract class restore_questions_activity_structure_step extends restore_activit
         $usage->preferredbehaviour = $quiz->preferredbehaviour;
         $usage->id = $DB->insert_record('question_usages', $usage);
 
-        $DB->set_field('quiz_attempts', 'uniqueid', $usage->id,
-                array('id' => $this->get_mappingid('quiz_attempt', $data->id)));
+        $this->inform_new_usage_id($usage->id);
 
         $data->uniqueid = $usage->id;
         $upgrader->save_usage($quiz->preferredbehaviour, $data, $qas, $quiz->questions);
diff --git a/mod/quiz/backup/moodle2/restore_quiz_stepslib.php b/mod/quiz/backup/moodle2/restore_quiz_stepslib.php
index b2ed15bec74..a80f87ce383 100644
--- a/mod/quiz/backup/moodle2/restore_quiz_stepslib.php
+++ b/mod/quiz/backup/moodle2/restore_quiz_stepslib.php
@@ -271,27 +271,19 @@ class restore_quiz_activity_structure_step extends restore_questions_activity_st
     }
 
     protected function process_quiz_attempt($data) {
-        global $DB;
-
         $data = (object)$data;
-        $oldid = $data->id;
-        $olduniqueid = $data->uniqueid;
 
         $data->quiz = $this->get_new_parentid('quiz');
         $data->attempt = $data->attemptnum;
 
-        $data->uniqueid = 0; // filled in later by {@link inform_new_usage_id()}
-
         $data->userid = $this->get_mappingid('user', $data->userid);
 
         $data->timestart = $this->apply_date_offset($data->timestart);
         $data->timefinish = $this->apply_date_offset($data->timefinish);
         $data->timemodified = $this->apply_date_offset($data->timemodified);
 
-        $newitemid = $DB->insert_record('quiz_attempts', $data);
-
-        // Save quiz_attempt->id mapping, because logs use it
-        $this->set_mapping('quiz_attempt', $oldid, $newitemid, false);
+        // The data is actually inserted into the database later in inform_new_usage_id.
+        $this->currentquizattempt = clone($data);
     }
 
     protected function process_quiz_attempt_legacy($data) {
@@ -306,8 +298,16 @@ class restore_quiz_activity_structure_step extends restore_questions_activity_st
 
     protected function inform_new_usage_id($newusageid) {
         global $DB;
-        $DB->set_field('quiz_attempts', 'uniqueid', $newusageid, array('id' =>
-                $this->get_new_parentid('quiz_attempt')));
+
+        $data = $this->currentquizattempt;
+
+        $oldid = $data->id;
+        $data->uniqueid = $newusageid;
+
+        $newitemid = $DB->insert_record('quiz_attempts', $data);
+
+        // Save quiz_attempt->id mapping, because logs use it
+        $this->set_mapping('quiz_attempt', $oldid, $newitemid, false);
     }
 
     protected function after_execute() {