I personally thought Grealish he massively helped the flow of our attacks in the first half especially, he seriously helps those around him play much better and it mostly goes less appreciated, despite going in for the halftime break losing we played very well in buildup and that was mostly due to Jack on/off the ball causing them problems.
Bernardo and Phil also played very well too never giving up on anything, Rodri was as solid as ever and his run helped create Bernie's goal, Ake also showed what we've been missing defensively in his absence.
Think all those players are the contenders today depending on what you preferred, personally though for me I thought Jack was very important for us today he brings a calmness to out creative players, we not only badly missed missed Rodri in that villa game but Jack too with Doku's injury.