One held down the victim, according to police. The other plunged a knife over and over into the victim's head and abdomen.
Now, both assailants in the attack outside a Farmingdale bar have been arrested on attempted murder charges, and the victim, 22, is nursing stab wounds in a hospital, Nassau County police said.
Police said that the stabbing, on Saturday at 1:35 a.m., happened as an argument escalated near 545 Fulton St.
Detectives identified Matthew K. Rumpf, 25, of 8 Madison Ln. in Carle Place as the stabber, and David Rosas, 25, of 7 Oakwood Ave. in Farmingdale, as the person who held down the victim for Rumpf.
Rumpf and Rosas fled in a Hyundai driven by Jeanine Rodenas, 24, of 22 New St. in Lynbrook, but cops found them driving in South Farmingdale and arrested all three - Rumpf and Rosas on attempted murder charges, Rodenas on a charge of obstructing governmental administration.
A police spokeswoman said the knife was recovered.
Rumpf and Rosas were to be arraigned Sunday, Rodenas on Feb. 8.