Grujic played the entirety of the Bundesliga affair as his side went a goal down before striking three without reply.
The midfielder drew plaudits for his performance that saw him make 61 passes, win 10 duels and complete all five of his dribbles.
It was also a successful weekend for Sheyi Ojo, who played 73 minutes of Rangers' 5-0 win over Hamilton Academical.
That result sent Steven Gerrard's team to the summit of the Scottish Premiership as they now sit two points clear of Celtic.
Staying in Scotland, striker Liam Millar started for Kilmarnock in their 1-0 win over Hearts on Saturday.