This is one of the tougher ties to call. One thing that's safe to expect is goals, with over 2.5 goals having been scored in four of both sides' last five Champions League outings.
In terms of the result, Sporting are in better form on the whole, although Niko Kovač has only been in the job a week or so. Dortmund still have an advantage on paper and Sporting found life tough against the last Bundesliga side they faced in the group stage, so we fancy a high scoring draw for this one. Sporting 2-2 Dortmund.