A jilted lover stalked and shot his ex-girlfriend and her new beau, ignoring the woman's desperate pleas for mercy early Saturday outside a seedy Bronx motel.

Joseph Kernizan, 42, was waiting when the couple emerged from the Holiday Motel around 3:10 a.m., and he blasted more than two dozen bullets at the helpless duo, witnesses and police said.

"Don't do it! Don't do it!" wailed Tracy Bennett, 38, before the shooter gunned down the twosome in the parking lot. The slain woman had an order of protection against Kernizan, police sources said.

Bennett and her boyfriend, Wayne Hamilton, 50, were about to leave in her white Toyota Camry when Kernizan sprinted out of the darkness and opened fire, the sources said.

Hamilton hopped from the passenger seat and tried to escape the hail of bullets that cut him down near the motel office, sources and witnesses said. Kernizan then turned his pistol on the weeping Bennett as she stood by her parked sedan, its motor still running, near Room 104. The doomed woman pleaded for her life before he opened fire.

"I looked out my window and saw a lady standing there," said Ricky Gugliotta, who was staying in a nearby room with some friends celebrating a pal's birthday. "She was begging him not to shoot her, but then he shot her twice and she went down."

Both Bennett, of Elmont, L.I., and Hamilton, a Milwaukee reggae musician known as Captain Barkey, died at the scene, police said.