Nadal routed Richard Gasquet 6-3, 6-0, 6-1 in the opening match of the series and Ferrer beat Gilles Simon 6-1, 6-4, 6-1 in the second.
Those decisions left France needing to sweep the final three matches to earn a second consecutive trip to the Davis Cup finals.
France sends Michael Llodra and Jo-Wilfried Tsonga against Spain's Feliciano Lopez and Fernando Verdasco in Saturday's doubles match. Nadal meets Simon and Ferrer goes against Gasquet in reverse singles Sunday.
Nadal, in his win over Gasquet, showed little effect of his tough four-set U.S. Open championship loss Monday to Novak Djokovic. Nadal, who is 9-0 lifetime in ATP matches with Gasquet, didn't face a break point and cashed in seven of his 16 break opportunities. The Spaniard took 79 percent of the points on serve.
Ferrer piled up eight breaks against Simon. He had to deal with six break points -- all in the second set -- and won 55 percent of the points when Simon served.
Spain is looking for a third Davis Cup title in four years. The Spaniards won the event in 2008 and 2009 but were eliminated 5-0 by France in the 2010 quarterfinals.
The Spain-France winner meets the survivor of a series between Argentina and defending champion Serbia. Argentina holds a 2-0 lead after matches in Belgrade Friday.
The Davis Cup finals are set for Dec. 2-4.
Argentina has 2-0 Davis Cup lead on Serbia
Nalbandian topped Viktor Troicki 6-4, 4-6, 6-2, 6-3 and del Potro defeated Janko Tipsarevic 7-5, 6-3, 6-4.
Troicki was a late substitute for world No. 1 Novak Djokovic, who was to have played the first singles match Friday but pleaded jet lag. His availability for Sunday's singles play is unknown.
Djokovic was key in helping Serbia win its first Davis Cup championship last year, but now the Serbs are one loss from elimination.
To keep that from happening, the Serbs must win Saturday's doubles in which Tipsarevic and Nenad Zimonjic are scheduled to play Argentina's Juan Ignacio Chela and Juan Monaco. If the Serbs win that match, the series will be decided Sunday in singles when Troicki -- or Djokovic -- face del Potro and Tipsarevic plays Nalbandian.
Nalbandian overcame seven double faults in winning two-thirds of the points on serve Friday. He saved nine of the 12 break points Troicki managed and lost his serve once after the second set.
Del Potro dropped just 16 points over 16 service games and had one break in each set in the win. He had 24 unforced errors against 42 winners.
The winner of the series heads to the Davis Cup finals against France or Spain. Spain owns a 2-0 lead in that semifinal.
Europe pulls close to GB&I for Seve Trophy
PARIS, Sept. 16 (UPI) -- Miguel Angel Jimenez and Pablo Larrazabal capped a big day for Continental Europe, which pulled close to Great Britain and Ireland in the Seve Trophy event.
Continental Europe grabbed 3 1/2 of the 5 points at stake in four fourball matches Friday and cut the Great Britain and Ireland team lead to 5 1/2-4 1/2 after two days of the four-day competition.
GB&I, which has won the last five Seve Trophies, needs to collect 14 points to retain the trophy. Continental Europe needs 14 1/2 to win.
But GB&I's day was shown more by Simon Dyson and Jamie Donaldson, who were up three after eight holes only to have Thomas Bjorn and Raphael Jacquelin fight back to halve the match for Continental Europe.
Europe's Peter Hanson and Alexander Noren were 5-and-3 winners over Robert Rock and Ian Poulter with consecutive wins on Nos. 13-15 sealing the match. And Matteo Manassero birdied the 18th hole to give him and Nicolas Colsaerts a 2-up decision over GB&I's Scott Jamieson and Ross Fisher.
Jimenez and Larrazabal were down early against Daren Clarke and David Horsey but Larrazabal won the 14th hole with a birdie and Jimenez took the 16th with another to take the point.
There are four greensomes and four foursomes matches scheduled for Saturday with 10 singles match play matches set for Sunday.
Three tied for Champions event lead in S. Korea
All three golfers birdied the final hole in the first round. Mark O'Meara, who had seven birdies on the day, is at 5-under 67 and five golfers are tied at 4-under.
Calcavecchia had eight birdies and two bogeys. He was 3-under after four holes but slipped back with bogeys at Nos. 6 and 8. He had five birdies in his final 10 holes.
Allen played the back nine of the Jack Nicklaus Golf Club Korea course first and was 1-under after eight holes. He was 5-under over the next four holes, however, capping the run with an eagle at the 550-yard par-5 third hole. His lone bogey came at No. 7 but he closed with a birdie at the ninth.
Peoples also overcame a front-side bogey, going 5-under in his last eight holes. That spurt included an eagle at the par-5, 528-yard 15th.
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