I would like to import the data published as a WMTS by the City of Vienna (http://data.wien.gv.at/) as a layer in QGIS. 

Is this possible, and if yes, how do I do it?

This is what I am talking about:

>http://data.wien.gv.at/formate/geowebservices.html

I could successfully load the WMS service, but I could not do the same with WMTS.