diff --git a/vsts/E2ETestsSetup/e2eTestsSetup.ps1 b/vsts/E2ETestsSetup/e2eTestsSetup.ps1
index de6a9edf0e..da62c6faf8 100644
--- a/vsts/E2ETestsSetup/e2eTestsSetup.ps1
+++ b/vsts/E2ETestsSetup/e2eTestsSetup.ps1
@@ -58,7 +58,16 @@ $rgExists = az group exists --name $ResourceGroup
 if ($rgExists -eq "False")
 {
     Write-Host "`nCreating resource group $ResourceGroup in $Region"
-    az group create --name $ResourceGroup --location $Region --output none
+
+    # Tagged as part of the creation itself, not afterwards: the scheduled cleanup in
+    # Azure/azure-iot-sdk-csharp vsts/resource-group-cleanup.yaml (which deletes leftover
+    # 'javasdkgate*' groups as well as 'dotnetsdkgate*' ones) uses 'CreatedOn' to tell a leftover
+    # group from one whose gate run is still in flight. Tagging in a second, separate call would
+    # leave a window where a run that dies in between produces an untagged group. That cleanup
+    # still reclaims such a group, but only via the slower 24-hour first-observed fallback rather
+    # than the 3-hour path. A single tag is passed here on purpose -- under the AzureCLI@2 task,
+    # '--tags' with several key=value arguments collapses them into one tag value.
+    az group create --name $ResourceGroup --location $Region --tags "CreatedOn=$([datetime]::UtcNow.ToString('o'))" --output none
 }
 
 $resourceGroupId = az group show -n $ResourceGroup --query id --out tsv