Let's compare him to Rosol.
Rosol did play this great match against Nadal.
But even in this match you saw the problems of his game, he choked one set away and was bad in two of five sets.
In the fifth set he made winners which were stunning but a lot of them were on the line, it was huge risk the whole set and it was on grass indoors.
You can not expect him to play at this level in following matches or tournaments.
After that match, Rosol lost the next match without playing great.
Janowicz did play a fantastic week until today.
He played great in MORE than one match or set.
He played great in several matches against different opponents.
He serves with ease tons of aces, he has touch, variety, good shotmaking.
Of course he won't play like this at every tournament but you can imagine more that he can repeat this level again and again. Not a every tournament on every surface, but at least from to time to time.
I don´t get this Jerzy and Rosol why people are comparing them no point
Rosol is ballbasher, that played match of his life vs Rafa and became ,,legend,, but he is relatively old and he is loosing to random mugs left-right, he won´t probably even reach top 50, i think 65 is his career high. His serve isn´t so special, just like any ballbasher in zone is hitting hard not only groundstrokes but also serve - but that´s it
Janowicz - totally different, he will be 22 in few days, so he has potential to do something in his career, top 10 potential at least, he is not ballbasher, he is more using drop shots and isn´t going for winners all the time - and serve wise he is in another leage - his serve right now is arguably most powerfull on the tour - he is hitting 220-235kph bombs all the time, only other player right now who can do it is Raonic, but even he is using more slice and variety and less pace.
JErzy is big server with weird game for big server, big future ahead of him.
Rosol is balbasher, who won´t achieve anything signifficant in his career, he will always be remembered for Rafa match but that´s it.