Argentina s River Plate players hold their trophy and celebrate winning the local soccer tournament at Monumental stadium in Buenos Aires, Argentina Thursday, Nov. 25, 2021. (AP)
River had not won the title since 2014.
Agustin Palavecino in the 32nd minute, Julian Alvarez in the 48th and Braian Romero in the 68th and 78th minutes scored the River goals.
River won the title in front of 70,000 fans with three rounds in hand. The Millionarios are now 12 points ahead of second-place Defensa y Justicia.
Gallardo, River's coach for the latest seven years, won 13 titles with the club, including the Copa Libertadores in 2015 and 2018. His contract is about to end, but after the match refused to say whether he will extend it.
(For more sports news and updates, follow Ahram Online Sports on Twitter at @AO_Sports and on Facebook at AhramOnlineSports.)