The 26 year-old, who had an unbeaten 25-fight record coming into the bout, was unfancied as he had no real names on his six-year career and was going in with a seasoned campaigner who is a veteran of six world title fights.
The Surrey-based southpaw looked sharp from the off though, marking up the German, 31, in the first round and opening a horrible gash on Sylverster’s forehead early on in the bout.
Proksa kept the pressure on the more experienced Sylvester who had no answer to his fast hands and combinations, taking far too much leather towards the end of the third, retreating to his corner splattered in blood.
His team then took the one minute interval to consult the former champion on whether he wanted to continue as he looked disconsolate on his stool and as the bell rang for the fourth round, the bout was called off.
Sylvester dropped his fifth loss in 40 contests after the stoppage, his second in a row and may now have to consider his options as Proksa moves on to a possible world title shot with his first major scalp.