The specified URL is not a top-level Web site

While doing site Backup and Restore in SharePoint 2013, i was getting the following error. Please note that the site collection is Host Name Site collection not Path based site collection.

The command i was giving is

PS C:\Windows\system32> Restore-SPSite http://sites.mytestsites.com/sites/mytestsite1 -Path "D:\Backup\MYTESTSITE1-PROD-20150210-2351.bak" -DatabaseName "SP13_Content_TESTSITEDB" -HostHeaderWebApplication "http://WFESERVERNAME" -Force 

The specified URL is not a top-level Web site. The backup and restore operations work only for top-level Web sites. Enter the URL for a site to try the

operation again.

At line:1 char:1

+ Restore-SPSite http://sites.mytestsites.com/sites/testSite1 -Path "D:\Backup\ ...

+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    + CategoryInfo          : InvalidData: (Microsoft.Share...dletRestoreSite:SPCmdletRestoreSite) [Restore-SPSite], SPException

    + FullyQualifiedErrorId : Microsoft.SharePoint.PowerShell.SPCmdletRestoreSite

The only thing that worked for me is 

- Deleting the existing site collection using the Remove-Spsite powershell cmdlet.

- Restoring the site from Backup using Restore-Spsite powershell cmdlet targeting to specific content DB

Remove-SPSite -Identity "http://sites.mytestsites.com/sites/TestSite1" -GradualDelete

Restore-SPSite http://sites.mytestsites.com/sites/MyTestSite1 -Path "D:\Backup\MyTestSite1.bak" -DatabaseName "SP13_Content_TestSitesContentDB" -HostHeaderWebApplication "http://WFESERVERNAME"

Hope this helps for some one who is having similar issue in backing up and restoring Host Name Site Collection (HNSC)

If someone finds a reason for this or is there any other way of doing this restore please let me know. 

Thanks,

Vinay.