something weird happened while practicing Rachmaninoff's C sharp etude

[sv3nno]

this etude is probably the most important piece i need to learn during the summer, and is almost finished.
(i'm 15 btw) i've always had this problem with playing scales. i just can't play them evenly, it's like my 4th fingers are dead. so i was practicing the second part of the piece at full speed, where the Agitato comes in. it's usually a nightmare for my right hand -.- it just sounds ugly. at one moment i got really depressed, started looking for examples of this piece played by others (different pianists, Rachmaninoff himself etc...) i stopped at this example at wikipedia https://en.wikipedia.org/wiki/File:Sergei_Rachmaninoff_performs_Rachmaninoff%27s_Prelude_in_C_sharp_minor,_Op._3.ogg
after listening to it, i started playing the second movement, and strangely i felt very relaxed. what scared me is that i then hit every single note perfectly, and evenly. 10 mins later, and i'm back to the old state of bad, bad playing. this has happened before, and only lasts until i'm in that weird relaxed state. has anyone got an explanation for this? it's really creeping me out.
thanks

[johnannsb]

sounds like you have very tense shoulders, i tend to find with any piece with lots of repeated notes or big chords a lot of people including myself can get very tense.
You have to be careful because this can end up causing a lot of pain if you strain a muscle. My advice is to take a break for a couple of days (you will be surprised how this can actually improve the piece) and then when you practice constant try to think about being relaxed, and make sure you shoulders are not creeping up: keep them loose.
If you play relaxed it looks a lot more professional and you look more in control which is always good.

[hmpiano]

One stage of learning a piece is to loosen control, stand back, and allow the music out.  Sounds like you achieved that.

[scherzo123]

happened to me too...

[mhoffman89]

Tension is a problem for many pianists. I know a pianist, fairly old, he developed a habit of rolling his shoulder during performance (sort of moving it slightly) to make sure he is relaxed. But you could always practice it in. Slow practice wont help so much with relaxation, but I suggest you take the part that's been worrying you and separate it into smaller sections, maybe by phrases, then at tempo and also faster, start going through each section repeatedly but at the same time making sure your shoulders and wrists are relaxed the whole time, after a while being relaxed will become a habit.... I'm only assuming this might be the problem, let me know if it was of any help to you.

[jesc]

Even in regular practice, it may suddenly happen that your fingers just start to do things exactly the way you want them to.

What I do is to catch that moment by repeating the passage immediately (while in the er... "zone") and observe the things I did right.   

[hmpiano]

The 'er...zone', that's a great term.  I'll remember it!

[jesc]

The 'er...zone', that's a great term.  I'll remember it!

The slang is "in the zone". Ok, I admit that I was really hesitant using it since it is an old phrase (way back 1999?).