diff --git a/client/resource_group/controller/controller.go b/client/resource_group/controller/controller.go
index 3415a0d6b8b4..aa585f85bff4 100755
--- a/client/resource_group/controller/controller.go
+++ b/client/resource_group/controller/controller.go
@@ -486,14 +486,31 @@ func (c *ResourceGroupsController) IsBackgroundRequest(ctx context.Context,
 
 	gc.metaLock.RLock()
 	defer gc.metaLock.RUnlock()
-	if bg := gc.meta.BackgroundSettings; bg != nil {
-		if len(requestResource) == 0 || len(bg.JobTypes) == 0 {
+	log.Info("[resource group controller] checkBackgroundSettings resource group", zap.String("resource group", resourceGroupName))
+	return c.checkBackgroundSettings(ctx, gc.meta.BackgroundSettings, requestResource)
+}
+
+func (c *ResourceGroupsController) checkBackgroundSettings(ctx context.Context, bg *rmpb.BackgroundSettings, requestResource string) bool {
+	// fallback to default resource group.
+	if bg == nil {
+		resourceGroupName := "default"
+		gc, err := c.tryGetResourceGroup(ctx, resourceGroupName)
+		if err != nil {
+			log.Info("[resource group controller] fallback to default resource group failed", zap.Any("resource group", gc))
+			failedRequestCounter.WithLabelValues(resourceGroupName).Inc()
 			return false
 		}
-		if idx := strings.LastIndex(requestResource, "_"); idx != -1 {
-			return slices.Contains(bg.JobTypes, requestResource[idx+1:])
-		}
+		bg = gc.meta.BackgroundSettings
+	}
+
+	if bg == nil || len(requestResource) == 0 || len(bg.JobTypes) == 0 {
+		return false
 	}
+
+	if idx := strings.LastIndex(requestResource, "_"); idx != -1 {
+		return slices.Contains(bg.JobTypes, requestResource[idx+1:])
+	}
+
 	return false
 }
 
diff --git a/tests/integrations/mcs/resourcemanager/resource_manager_test.go b/tests/integrations/mcs/resourcemanager/resource_manager_test.go
index b429ff4f442f..f720d46894af 100644
--- a/tests/integrations/mcs/resourcemanager/resource_manager_test.go
+++ b/tests/integrations/mcs/resourcemanager/resource_manager_test.go
@@ -1189,6 +1189,23 @@ func (suite *resourceManagerClientTestSuite) TestSkipConsumptionForBackgroundJob
 		re.Contains(resp, "Success!")
 	}
 
+	resp, err := cli.ModifyResourceGroup(suite.ctx, &rmpb.ResourceGroup{
+		Name: "default",
+		Mode: rmpb.GroupMode_RUMode,
+		RUSettings: &rmpb.GroupRequestUnitSettings{
+			RU: &rmpb.TokenBucket{
+				Settings: &rmpb.TokenLimitSettings{
+					FillRate:   1,
+					BurstLimit: -1,
+				},
+				Tokens: 1,
+			},
+		},
+		BackgroundSettings: &rmpb.BackgroundSettings{JobTypes: []string{"lightning", "ddl"}},
+	})
+	re.NoError(err)
+	re.Contains(resp, "Success!")
+
 	cfg := &controller.RequestUnitConfig{
 		ReadBaseCost:     1,
 		ReadCostPerByte:  1,
@@ -1201,10 +1218,15 @@ func (suite *resourceManagerClientTestSuite) TestSkipConsumptionForBackgroundJob
 
 	resourceGroupName := suite.initGroups[1].Name
 	re.False(c.IsBackgroundRequest(suite.ctx, resourceGroupName, "internal_default"))
+	// test fallback.
+	re.True(c.IsBackgroundRequest(suite.ctx, resourceGroupName, "internal_lightning"))
+	re.True(c.IsBackgroundRequest(suite.ctx, resourceGroupName, "internal_ddl"))
 
 	resourceGroupName = "background_job"
 	re.True(c.IsBackgroundRequest(suite.ctx, resourceGroupName, "internal_br"))
 	re.True(c.IsBackgroundRequest(suite.ctx, resourceGroupName, "internal_lightning"))
+	// test fallback.
+	re.False(c.IsBackgroundRequest(suite.ctx, resourceGroupName, "internal_ddl"))
 
 	c.Stop()
 }