His form really fell off during the Ballon'dor talk. Seems to be playing without all that tension again.
His form has been difficult to accurately rate this season IMO, scoring-wise he's been as good as ever, but the rest of his game only really kicked on from November onwards (and in a couple of games before that which I'll mention). Started his scoring form in the second half of September after what seems to have become a customary slow start to the season from him, but the team (him included) were not playing very well (apart from the Galatasaray away game in the CL where he was magnificently unstoppable) and were fortunate not to have dropped more points than they did (v Betis, Granada, Villarreal, Elche). So for September I could put a lot of other players ahead of him that were performing at a higher level. Then in October is when his scoring form really started to pick up, but he couldn't make a mark in two key games which they both lost (v Atlético and Barça), a lot of his goals at that point came from penalties as well (5 already, I believe). The 7-3 v Sevilla at the end of that month was the turning point IMO, he scored a hat-trick and his all-round game came to life from that point onwards. For October I wouldn't have him down as the top performer (Diego Costa was too good in this period and has the edge in scoring the winner in the direct confrontation between them) but he's definitely a close #2. November was undoubtedly his, excellent performances (esp. v Rayo) and goalscoring consistency. December saw him score less, but he played quite well (except, ironically, against Celta where he scored twice late on). January has been equally tough, but he was great v Betis and now Granada and scored two great goals in these games.
As far as forwards go, I'd divvy it up like this between the leading men of the 3 title candidates:
August:
Diego Costa
September:
Messi, Diego Costa
October:
Diego Costa, Cristiano
November:
Cristiano, Diego Costa
December:
Diego Costa, Cristiano
January: all three playing very mixed games, but
Cristiano should hold unless Messi manages to produce something profoundly legendary today (which is doubtful), as taking into account his Copa del Rey form he still has a chance, Diego Costa on the other hand was nowhere near his form of the 1st half of the season.
The way it is currently looking, RM are on title-winning form and it's coincided with Cristiano being less emphasized as the end point of every final pass, but him taking part in the build-up more often. His away form has also reached the same level as back in their only title-winning season (2011/12), so if that keeps up it will need a near flawless course (and far more from Messi as he's behind by quite a lot due to his injuries) from either of the other two contenders or Cristiano himself to underperform in order to surpass the season he's having. If Diego Costa can somewhat replicate the 1st half of his season then he'll likely equal or surpass Cristiano's season in individual terms, but I doubt he (and for that matter his club) can maintain the insane pace set by the "Big Two". We shall see, but honestly it wouldn't surprise me in the least to see Atlético drop points tonight away to Rayo (as poor as they've been, they're incredibly unpredictable at home) with Costa unable to make much of a dent.