Updated at 11:39 a.m.
Former New York City comptroller Bill Thompson (D) ended his campaign for mayor Monday and endorsed Public Advocate Bill de Blasio (D).
De Blasio beat Thompson on primary day last week by 14 points, and as of now has more than the 40 percent of the vote he needs to avoid a runoff (40.3 percent). Thompson said he is stepping down to avoid a lengthy vote-counting process that would take far too long to resolve.
"Bill de Blasio and I want to move our city forward in the same direction," Thompson said. "Today, I'm proud to stand next to a great New Yorker and throw my full support behind him."
Even as he conceded, though, Thompson made clear that he was not pleased with the slow pace of vote-counting in New York. He said the city needs to address the matter so that a similar situation doesn't occur in future elections.
Nevertheless, polls indicated de Blasio would have been a clear favorite in a runoff with Thompson, the 2009 nominee who narrowly lost to Mayor Michael Bloomberg (I) four years ago. Thompson also received pressure from top New York City Democrats to drop out and avoid a bruising three-week runoff.
In the general election, de Blasio will face Republican Joe Lhota, a former chairman of the city's Metropolitan Transportation Authority.
The Democrat enters that race with big advantage, but the city hasn't elected a Democratic mayor in two decades.