From what I could tell yesterday he was deployed at the tip of a midfield three, with pogba to the left and Herrera to the right (doing a job on Hazard). This is the only position he should be played. He can work well in a midfield three but due to his lack of pace and positional awareness he's never going to be suited to a two.
For me, yesterday he was absolutely fantastic. There a few reasons I dislike Fellaini and cringe when I see his name in the line-up and they are because his running style is very laboured, he always looks as though he's moving in slow motion, which to me makes him seem lazy, I very rarely see him sprint. He has the strength and build to be a dominant centre midfielder but he rarely makes the most of these traits.
Normally he's quite easily beaten to the ball, dispossessed in possession and more often than not he's beaten in the air by much smaller players (he very rarely even jumps anymore, possibly because of the elbow-fouls he seems to concede). However, yesterday he used all of his assets perfectly. He shielded the ball against 2 or even 3 players on occasion, he made some good tackles, he won the majority of second balls and only made the one mislaid pass that I saw.
If he could put in more of these performances then he could become a mainstay in a three man midfield for us and i'd be very happy for him, whatever people may say about him, he has the never say die attitude that I expect from a Manchester United player. If he could put these types of performances in on a weekly basis then i'd be more than happy for him to stay.