Nadal defeated Karen Khachanov 6-3, 7-6(7), while Granollers and Lopez defeated recent Paris Masters runners-up Khachanov and Andrey Rublev 6-4, 7-6(5) on Tuesday.
Meanwhile, Canada became the first team to enter the quarter-finals after defeating USA 2-1 on Tuesday evening.
The Canad beat Italy on Monday in Group F and thanks to singles wins from Vasek Pospisil and Denis Shapovalov, downed the USA. Pospisil defeated Reilly Opelka 7-6 (5), 7-6 (7) while Shapovalov beat Taylor Fritz 7-6 (6), 6-3 to help Canada cement their place in last eight.
In Group A, the doubles pair of Pierre-Hugues Herbert/Nicolas Mahut clinched a 2-1 win for France 6-7(4), 6-4, 7-5 against Japan's Ben McLachlan/Yasutaka Uchiyama.
France's Jo-Wilfried Tsonga beat Yasutaka Uchiyama 6-2, 6-1 and Japan's Yoshihito Nishioka beat Gael Monfils 7-5, 6-2 to setup the deciding doubles match.
In Group D, Australia beat Colombia after Nick Kyrgios and Alex de Minaur both won in straight sets. Kyrgios beat Alejandro Gonzalez 6-4, 6-4 and De Minaur swept Daniel Elahi Galan 6-4, 6-3.
Argentina thrashed Chile 3-0 behind a 6-4, 6-3 Guido Pella win against Nicolas Jarry, a 6-2, 6-2 Diego Schwartzman victory against Cristian Garin and a 6-3, 7-5 doubles victory for Maximo Gonzalez/Leonardo Mayer versus Nicolas Jarry/Hans Podlipnik-Castillo.
In Group E, Alexander Bublik/Mikhail Kukushkin provided Kazakhstan with a 2-1 win against the Netherlands with a 6-4, 7-6(2) victory against Robin Haase/Jean-Julien Rojer. Earlier in singles, Haase had defeated Bublik 7-5, 3-6, 7-6(5) and Kukushkin beat Botic Van de Zandschulp 6-2, 6-2.
( With inputs from IANS )