The victim, 35, was attacked on MacNish Street near Elmhurst Avenue about 9 p.m., NYPD officials said.
When he stumbled into the hospital, doctors found the stab wound was so deep it pierced his heart, police said.
He required surgery and was initially listed in critical condition until doctors managed to stabilize him, police said.
The circumstances of the stabbing weren't immediately clear.
There were no immediate arrests, police said Tuesday morning.