Lukaku and Martial were our best goals/assists partnership last season. They even matched some record that Yorke and Cole had about assisting each other.
Spurs, Watford, Burnley, CSKA, Arsenal are games off the top of my head where they worked together to help us win. I'm sure there are more games I can't remember.
Liverpool also. We have gotten the best out of Lukaku when we have played with something like 2 upfront, and especially with Alexis. It helps Sanchez as well because his pressing game works better in the center of the field, where his energy actually makes a differnce.
Our wingers dont press under Mourinho, they are supposed to cover the channels first and foremost.
Martial to the left with Sanchez up front with Lukaku (if he has to play) is probably the best we can do right now IMO. Rashford, Mata and Lingard can battle it out for RW.
Dont think Mourinho ever will go for this consistently though. It would expose the CMs too much for his liking and tbh Matic cant ever play in such a system, which he always will do under Mourinho anyhow. Sigh.....