Bob O’Connor won the Democratic Party’s nomination for mayor of Pittsburgh last night,… Bob O’Connor won the Democratic Party’s nomination for mayor of Pittsburgh last night, defeating Bill Peduto, Michael Lamb, and four other candidates.

Former councilman O’Connor, 60, will now square off with Republican Joseph Weinroth, who ran unopposed in the primary, in November.

“For the city of Pittsburgh to be successful, the No. 1 thing we need to believe in is ourselves,” O’Connor said in a victory speech at the Sheraton Station Square Hotel.

Tuesday marked O’Connor’s third consecutive attempt to run for mayor of Pittsburgh. He lost twice to Mayor Tom Murphy, in 1997 and 2001.

“My mom always told me that three’s a charm,” O’Connor said to a standing crowd of supporters and volunteers. He attributed the energy behind his victory to a strong grass-roots campaign.

O’Connor thanked his family, the people who ran his campaign, business and labor leaders, and everyone who worked to get him nominated.

Following O’Connor’s speech, confetti and blue balloons were released over the crowd. O’Connor also thanked County Chief Executive Dan Onorato, who was in attendance, for his endorsement during the campaign.

O’Connor, a Squirrel Hill resident, pledged that he would be everyone’s mayor and concluded his speech with fist pumping and passionate yelling.

Sarah Bingler contributed to this report.