Eder Militao's third-minute header was enough for Carlo Ancelotti's to secure the win against a struggling Getafe side, who are 16th in the table with just two wins from eight games.
River's quest began in subdued fashion with a 3-0 defeat away to Liga de Quito in Group D, but Marcelo Gallardo's charges quickly rediscovered their best form.
Peru's Binacional were thrashed 8-0 and 6-0 while the Millonario also picked up four points against a Sao Paulo team featuring Dani Alves, pushing the Brazilians into third place and the Copa Sudamericana while River qualified in first.
In the last-16 stage River dominated over Athletic Paranaense, racking up 39 shots over two legs to their opponents' 14. Goals proved hard to come by, though, and after tying the first leg 1-1 in Coritiba a single strike from Nicolas de la Cruz saw the Argentines over the line. Uruguay's Nacional were then put to the sword, with River's 2-0 home win followed by a 6-2 thrashing in Montevideo to produce an emphatic aggregate victory for the Millonario.
Goal 00:30 EAT 03/01/2021 While both Superclasico rivals have one eye on their upcoming Libertadores matches, they will still be desperate to put in a strong display
Argentine football continues across the festive season this December and January with the playing of the Copa Diego Armando Maradona.
Boca was crowned 2019-20 league champions in March after coming out on top during the 23-game season.
The Copa Superliga was scheduled to follow on from the regular campaign, but was scrapped after just one game as football came to a halt.
This season’s action began with a new cup format, renamed after Diego Maradona following his death in November, where six groups of four teams competed for 12 places in the Campeon de Copa phase.