The injured Nadal lost in the Australian Open quarterfinals 6-4, 6-2, 6-3 Wednesday to fellow Spaniard David Ferrer at Rod Laver Arena in Melbourne. Nadal was trying to win his fourth straight Grand Slam tournament over two seasons.
"That's disappointing for him, really," the 72-year-old Laver told The Associated Press from his home in Carlsbad in northern San Diego County. "In a way, that was an effort to put all those tournaments together through last year. It really was a good performance. I had him as being favored, even to beat Federer, the way he was playing. He just has got a game that's difficult for Roger.
"I'll be darned. I thought he'd come all the way through, but he didn't," Laver said. "They were all counting that he was going to be the defending champion in all four tournaments."
Laver said he knew Nadal had been ill recently and that one of his knees has given him trouble.
"It looked like he was playing well," Laver said.
Laver is the last man to win a true Grand Slam, made up of the Australian Open, French Open, Wimbledon and the U.S. Open in a calendar year. He did it twice, as an amateur in 1962 and again in 1969.
For Nadal to fall short of holding all four Grand Slam titles at the same time shows what an accomplishment it was for Laver, who's still known as "Rocket."
Laver has always diplomatically maintained that it's harder to win a true Grand Slam than to win four straight Grand Slam tournaments over two seasons.
"It is certainly tougher to win in the calendar year," Laver said. "There's a time frame. You don't have any chance unless you start off winning the Australian Open. Otherwise, it doesn't qualify as the Grand Slam.
"Again, the same thing applies with what he did. It takes an unbelievable effort. You've got to be fortunate not to have any injuries or any bloody sicknesses. You've got to prepare yourself to play in four matches. Depending on the draw you've got, that could give you trouble. There are a lot of little things that come along."
Two years ago, the four men Laver beat with his powerful left arm in his 1969 Grand Slam -- Spaniard Andres Gimeno and fellow Aussies Ken Rosewall, John Newcombe and Tony Roche -- joined Rocket Rod at a lunch at the Australian Open to celebrate the 40th anniversary of his second Slam. Laver also presented Nadal with the trophy after he beat Roger Federer in the title match.