The match of the day saw the gritty 5-foot-8 Ferrer outlast 6-foot-6 world No. 11 Juan Martin del Potro in five sets, 6-2, 6-7 (2-7), 3-6, 6-4, 6-3, on red clay at Seville's Olympic Stadium, where 27,000 spectators were on hand, including King Juan Carlos.
The world No. 2 Nadal gave the hosts a quick 1-0 lead earlier in the day by thrashing 26th-ranked helpless Argentine Juan Monaco, 6-1, 6-1, 6-2, in 2 hours, 27 minutes.
This star-packed final features three of the top-11 players in the world in Nadal, Ferrer and del Potro. The 25-year-old Nadal and 29-year-old Ferrer are now a combined 27-0 on clay for Spain in Davis Cup play.
Four-time champion Spain can clinch its third Davis Cup title in four years with a doubles victory on Saturday, when left-handers Feliciano Lopez and Fernando Verdasco battle an Argentine tandem of former Wimbledon singles runner-up David Nalbandian and Eduardo Schwank.
Argentine captain Tito Vazquez left the oft-injured former top-five star Nalbandian out of the singles lineup on Friday. The world No. 64, however, should be available, if needed, on Sunday. The 29-year-old Nalbandian hasn't played anywhere since mid-October.
On the court Friday, Ferrer rolled in the opening set against del Potro, who was unable to find his rhythm until the second stanza. The formidable del Potro got back into the match with a win in the second-set tiebreak.
Del Potro then appeared to have Ferrer on the ropes by taking the third set, which the Spaniard led 3-1 before the towering Argentine fought back with a pair of breaks en route to a 5-3 advantage.
A fit Ferrer, however, roared back to win the next two sets and whip the home crowd into a frenzy on a chilly night in Seville.
Ferrer broke del Potro to capture the fourth set in 10 games and then cruised in the fifth, as the Argentine slugger started to show signs of fatigue. Ferrer jumped out to a comfortable 5-1 lead in the final stanza and ultimately closed out the rubber on his first match point after a grueling 4 hours, 46 minutes of tennis.
A deflated del Potro left the court while wiping away some tears.
The 23-year-old del Potro wound up with 11 aces, but he also had his big serve broken on eight occasions, compared to his five breaks of Ferrer. The Argentine struck 24 more winners (71-47), but also tallied seven more unforced errors (55-48).
In the lopsided Nadal-Monaco affair, the Spanish great piled up seven breaks and did not face even one break point against on Friday.
After cruising through the first two sets, the six-time French Open champ picked up a service break for a 3-2 lead in the third following the best point of the match, an incredible rally that finally concluded with a backhand winner into an open court on Day 1. Monaco took a spill trying to get to the winning shot and wound up with bloody scrapes on both knees.
"The best part of my game was I didn't make mistakes," Nadal said.
Nadal is now 19-1 lifetime in Davis Cup singles, including 19 straight wins and an unbeatable 15-0 record on his beloved clay.
The 10-time Grand Slam champion was this year's French Open winner and Wimbledon and U.S. Open runner-up.
Sunday's reverse singles currently call for Nadal to meet del Potro and Ferrer to take on Monaco.
Powerful Spain is 3-0 all-time versus Argentina, including a road victory in the 2008 Davis Cup finale in Mar del Plata. The Spaniards have won four of the last 11 Davis Cup titles, while Argentina is still seeking that elusive first-ever championship, having gone 0-3 in its previous finals (1981, 2006, 2008).
Spain has won 20 straight home ties, with its last home loss coming against Brazil back in 1999.
The Spaniards are captained by former French Open champ Albert Costa.