Nadal and his fellow Spaniards are playing host to Argentina on an indoor red clay surface at Seville's Olympic Stadium. The best-of-five showdown will conclude on Sunday.
Nadal-Monaco will be followed on Friday by the second opening singles rubber, which will pit four-time champion Spain's world No. 5 star David Ferrer versus Argentina's former U.S. Open champ Juan Martin del Potro.
Argentine captain Tito Vazquez left oft-injured former top-five star and former Wimbledon runner-up David Nalbandian out of the singles lineup.
Saturday's doubles will pit a left-handed Spanish tandem of Feliciano Lopez and Fernando Verdasco against an Argentine duo of Nalbandian and Eduardo Schwank, while Sunday's reverse singles currently call for the world No. 2 Nadal to meet the 11th-ranked del Potro and Ferrer to take on the No. 26 Monaco.
Nadal, Ferrer and del Potro represent three of the top-11 players in the world.
Spain is 3-0 all-time versus Argentina, including a victory in the 2008 Davis Cup Final in Mar del Plata, where the Argentines were the hosts. The Spaniards have won four of the last 11 Davis Cup titles, while Argentina is still seeking that elusive first-ever championship.
Powerful Spain is captained by former French Open champion Albert Costa.