VINA DEL MAR, Chile -- Rafael Nadal put himself through a twin workout on Friday to test his sore left knee, defeating fellow Spaniard Daniel Gimeno-Traver 6-1, 6-4 to reach the semifinals of the VTR Open.
Nadal, who is making his comeback to the tour after seven months off to nurse the knee injury, followed that with a doubles victory, teaming with Juan Monaco to win 6-3, 6-4 over the Argentine pair of Carlos Berlocq and Leonardo Mayer.
Those two wins meant Nadal had played five matches in four days. The knee is still hurting but he felt like he was making progress.
"I felt better today than the first day, so that's a positive thing," Nadal said. "That's a thing that gives me confidence and hope for the future that we're going in the right way. After seven months out of competition, even if I don't have the pain in the knee, at the beginning you feel slower, you feel more tired than usual so you need time to adapt. That's the thing. I need time to do it. I still feel pain in the knee some days and that's something we hope and think will be improving week by week."
Nadal will play France's Jeremy Chardy in the singles semifinals on Saturday. Should he win that, the Spaniard will then face another busy day on Sunday with a singles final plus the doubles decider against the Italian pair Paolo Lorenzi and Potito Starace.
The Spaniard's goal is to get back to the top and challenge the other three of tennis' Top Four: Novak Djokovic, Roger Federer and Andy Murray.
Nadal took the court Friday with temperatures hovering around 30C (85F) in the middle to the South American summer. He is likely to encounter similar temperatures when he plays next week in Sao Paulo, Brazil, and later this month in Acapulco, Mexico.
Nadal has said he's not focused on results as he uses the Latin American clay-court events to hone his game. But most fans will expect the most dominant clay-court players in history -- he has won 93 per cent of his singles matches on the surface -- to win all three tournaments and show he's ready to challenge for an eighth French Open title come May.
He will turn 27 in the middle of the French Open.
Nadal was asked Friday about testing for performance-enhancing drugs. He said he wants cheats caught, and clean athletes protected.
"Not everyone has to pay for some sinners," Nadal said.
Nadal said earlier this week that he had passed six blood and urine tests since losing on June 28 at Wimbledon -- his most recent tournament before the current one in Chile.
Nadal, an 11-time Grand-Slam winner, said it should be made public who is being tested and how frequently.
"If I go through a lot -- or very few doping controls -- people should know," he said. "Though I went for seven months without competing, I went through a lot of tests.
"I don't have to justify anything," he added. "This information should be open the public."
All top tennis players are subject to being tested without warning. The admission last month by Lance Armstrong that he used banned substances in all seven of his Tour de France victories has increased the focus on doping in all sports.
"The important thing is that those who are cheating, pay for their cheating," Nadal said.