"We beat the odds in 1994 and will do it again in 2018," Pataki said in this tweet.
Pataki was referring to his upset win over then-Gov. Mario Cuomo in 1994. Pataki served three terms as the last Republican governor of New York.
Molinaro is expected to face Cuomo's son, Democrat Andrew Cuomo of New Castle, in November's general election.
"To our friends in the media who have written the story of 'Molinaro's a great guy but he can't win,' you wrote the same stories about me in 1994," Pataki said in his speech. "And just like in 1994, in November of 2018 you're going to say 'How did this happen?'"
Molinaro headlined the opening session of the state Republican convention at the Ziegfeld Ballroom in Manhattan, delivering a 35-minute speech blasting Cuomo after party delegates made him the unanimous GOP nominee for governor.
Molinaro's running mate, former Rye deputy mayor Julie Killian, received the lieutenant governor nomination Wednesday afternoon.
Democrats gathered Wednesday on Long Island for their state convention. Their convention features former presidential candidate Hillary Clinton of Chappaqua on Wednesday before Cuomo accepts his party's nomination on Thursday, May 24.
Click here to follow Daily Voice Pound Ridge and receive free news updates.