On 2 March 2008, he made his senior debut for Borac head coach Milovan Rajevac in a league match against Hajduk Kula.

Otherwise, Lazović saw little playing time until the arrival of coach Robert Prosinečki, after which he was named as best young player in the Serbian Superliga.

In the semi-final of the 2011–12 Serbian Cup, On 11 April 2012, he scored a goal against historic rival Partizan, in a game which Red Star won 2–0.

On 4 July 2012, Lazović signed a three-year contract extension, ending speculation about a possible transfer after Red Bull Salzburg made an offer for him.

During the 2011-12 Europa League campaign, Lazović contributed with assists against Naftan Novopolotsk and played full matches against Omonia and Bordeaux.

Although a period of instability followed at Red Star, Lazović remained in the starting eleven even after a quick succession of coaches: Robert Prosinečki, Aleksandar Janković, and Ricardo Sá Pinto.

After the departure of Nenad Milijaš and suspension of Nikola Mijailović during season, Lazović was appointed as new captain of Red Star Belgrade.

On 14 January 2015, it was announced that at the end of the season, after six years in Red Star Belgrade, as a free player, Lazović would sign A multiyear contract with Serie A club Genoa.

[17][better source needed] On 5 June 2012, during his third game for the senior team, Lazović scored an impressive goal against Sweden which was disallowed by the referee.