Rafael Nadal struggled into the Brazil Open final on Saturday by downing Argentine lucky loser Martin Alund in three sets and later said he was handicapped by nagging knee pain. The former world number one, who is recovering from a left knee injury, battled hard to dismiss his 27-year-old opponent, who is ranked 111 in the world, winning 6-3, 6-7 (2/7), 6-1 in nearly two hours.
Sunday's final will pit the 26-year-old Spanish star against Argentine David Nalbandian, who whipped Italian Simone Bolelli 6-3, 7-5 in 85 minutes in the other semi-final.
It will be Nadal's second singles final since his comeback from a seven-month absence due his left knee injury and then illness.
Last week, he competed in the Vina del Mar Open in Chile, losing the singles and doubles finals.
At a post-match press conference, Nadal said that while he was physically prepared for tomorrow's final, "my knee is not".
"I don't think I am the favourite at all. The conditions are much more favourable for David (Nalbandian)," he said. "I still have discomfort. Today the knee did not respond well. And in those circumstances, not being able to move well, to attack the ball, it will be very difficult."
"I am going to do what I can... But I think it is going to be a very complicated match for me."
The 31-year-old Nalbandian, a former world number three who now languishes in 93rd place in the ATP rankings, has also been plagued with injuries.