- World rankings
Nadal plays down top-four chances
The 11-time grand slam champion claimed his first title in just his second tournament since returning to the sport, beating David Nalbandian to lift the Brasil Open on Sunday.
But while the Spaniard is buoyed by success in South America after spending seven months on the sidelines, he has admitted that the knee injury is still not fully healed and refuses to set goals beyond his next tournament.
"I'll definitely enjoy this one because of all the problems that I've gone through with the knee," said Nadal, who claimed the second title of his career in Sao Paulo in 2005. "When I won for the first time here I was just starting and hopefully this will mark a new beginning.
"When the knee is feeling better like today I feel like that I can do more of the things that I used to do my entire life," he said. "If the pain is bearable like it was today, then it's fine."
Asked if he was ready to compete with the world's top four once more, Nadal said: "We are going to see how the knee responds and then take stock.
"I don't have any problem playing against better rivals because I accept that I can lose. Losing is not a problem for me. I just need time to continue improving and return to a more competitive level."
Men's rankings: 1. Novak Djokovic (SRB), 2. Roger Federer (SUI), 3. Andy Murray (GBR), 4. David Ferrer (ESP), 5. Rafael Nadal (ESP), 6. Tomas Berdych (CZE), 7. Juan Martin Del Potro (ARG), 8. Jo-Wilfried Tsonga (FRA), 9. Janko Tipsarevic (SRB), 10. Richard Gasquet (FRA)
Women's rankings: 1. Serena Williams (USA), 2. Victoria Azarenka (BLR), 3. Maria Sharapova (RUS), 4. Agnieszka Radwanska (POL), 5. Li Na (CHN), 6. Angelique Kerber (GER), 7. Sara Errani (ITA), 8. Petra Kvitova (CZE), 9. Samantha Stosur (AUS), 10. Caroline Wozniacki (DEN)