The Spaniard bore little resemblance to the player who once terrorised his opponents as he slumped to a 6-1, 7-6 defeat by Russia's Nikolay Davydenko.
In the Dubai Open semis, Federer plays Tommy Haas, while Youzhny takes on Robin Soderling.
Sumit Nagal was handed a straight-set defeat by Canada's Milos Raonic in the opening round of the BNP Paribas Open.
Rafael Nadal has broken lots of records in his career but they do not matter to the Spaniard, who on Wednesday strolled into the French Open semi-finals after compatriot Pablo Carreno Busta quit with an injury less than an hour into the match.
The Spaniard acknowledged he will have his work cut out to beat the world number one in Saturday's Masters Cup semi-final.
Nadal committed 30 unforced errors to Schwartzman's 17 and had his serve broken five times.
Rafael Nadal beat Andre Agassi 7-6, 6-2, 6-4 in the third round.
'You can't be frustrated all the time because the neighbour has a bigger house than you, or a bigger TV or better garden. That's not the way that I see the life, you know'
Rafael Nadal had expected to race to a record fifth successive French Open title before Roger Federer cast a shadow over the Spaniard's Roland Garros prospects.
Frenchman Paul-Henri Mathieu gave the defending champion a nasty 20th birthday fright before the Spaniard prevailed 5-7, 6-4, 6-4, 6-4.
World number one Rafael Nadal held off a late challenge from Briton Andy Murray to move to the brink of a record fifth consecutive title at the Monte Carlo Masters with a 6-2, 7-6 semi-final win on Saturday.
World number one Rafael Nadal needed two tie-breaks to outlast Stanislas Wawrinka 7-6 7-6 at the Sony Ericsson Open on Tuesday, the Spaniard's win completing an ominous march into the quarter-finals for the top seeds.
Nadal, is known to have a superior win-loss record over most top players (including Andy Murray and Novak Djokovic), but believe it or not, there are players on the circuit who have an edge over Nadal.
Next up for the 35-year-old will be another American in 39th-ranked Tommy Paul with a potential semi-final clash against top-seeded Russian Daniil Medvedev, who he defeated in the Australian Open final from a two-sets deficit.
Nadal avenged his defeat to the 20-year-old Greek at the same stage of the Madrid Open a week ago
Images from the men's singles action at the Wimbledon Championships on Saturday.
Rafael Nadal needs to play more aggressively if he is to claim a record-extending 11th French Open title as a pack of young wolves is breathing down his neck, according to three-time Roland Garros champion Mats Wilander.
Alcaraz has not gone beyond the quarter-finals in his three previous visits to Melbourne, but that has not stopped the world number three from dreaming of glory in the Jan. 12-26 event.
Fourth-ranked Carlos Alcaraz and Norway's world number seven Casper Ruud also have a shot at top spot.
IMAGES from the Australian Open matches played on Wednesday.
'...but at the same time we were able to understand that personal relationships are more important than sometimes professional things.'
It was Nadal's 50th trophy on clay court, his 70th overall and his first title in almost a year
'The world is suffering in general, so we can't complain'
As Real Madrid star striker Cristiano Ronaldo watched, the World No 4 Nadal went past Italian Bolelli to set up a quarter-final clash against 10th seed Grigor Dimitrov.
The Eiffel Tower was still standing, the River Seine was flowing away to the sea and the traffic still clogged the Peripherique -- and Rafael Nadal still ruled Roland Garros on Tuesday.
"I don't think I can ever win all four Grand Slams in a year," the Spaniard said on the eve of the ATP tournament in Chennai.
Medvedev squandered a two-set lead against Nadal in their previous meeting in the Melbourne final in January, allowing the Spaniard to clinch his 21st Grand Slam title.
'I feel happy to be part of this rivalry, but at the same time, I played even more matches with Novak (Djokovic) than with Roger in such important matches, too'
Novak Djokovic is ready to challenge Jannik Sinner and Carlos Alcaraz at the Grand Slam stage when he returns to action at the Australian Open after an underwhelming campaign this year, the 24-times champion said.
World number two Murray, who smashed a frame in anger in the final game, said the proximity of next week's Davis Cup final on a claycourt in Ghent had not been a factor in his defeat.
The Spaniard, who has won 88 of his last 89 matches on clay, feels he still has plenty of room for improvement.
Rafael Nadal extended his astonishing winning run on clay to 42 consecutive sets as he reached the semi-finals of the Barcelona Open with a 6-0, 7-5 victory over Slovakia's Martin Klizan.
Rafael Nadal has booked his place at the World Tour finals after winning a record eighth French Open title, the ATP said on Monday.
Rafael Nadal continued his resurgence with a thrilling 2-6, 6-4, 6-2 victory over world number two Andy Murray on Saturday to reach the final of the Monte Carlo Masters.
Nadal surpassed the haul of Roger Federer and Novak Djokovic.
Russian seventh seed Daniil Medvedev, the 2023 Miami champion who arrived this year fresh off a run to the Indian Wells semi-finals, crashed out at the first hurdle as he fell 6-2, 6-3 to Spaniard Jaume Munar.
Rafael Nadal continued his quest for a maiden Paris Masters title when he survived a second set blip to beat Uruguay's Pablo Cuevas
Rafa Nadal's return to form was stopped in its tracks when he lost his opening match at the Aegon Championships to Ukraine's Alexandr Dolgopolov 6-3, 6-7(6), 6-4 on Tuesday.
'Djokovic had an impeccable year in 2011 as well as he is having in 2015, says Nadal.
