Rafael Nadal continued his comeback from a serious leg injury by beating Joao Souza in straight sets at the clay court Brazil Open in Sao Paulo.
The 11-time Grand Slam champion won 6-3 6-4 in 79 minutes, breaking serve once in each set.
The top-seeded Spaniard, who missed over seven months of action because of a bad knee, was rarely troubled on his own serve, saving just one break point against the world No 140 from Rio de Janeiro.
He broke in the sixth game of the first set, and ninth in the second, before sealing a straightforward win on his first match point.
The 26-year-old said: "It was an important victory for me.
"The conditions are very difficult. The court is very fast, the ball too."
As for the state of his knee, he added: "Today, it was acceptable, normal. Let's hope it will be the same tomorrow. The important thing is that it does not hurt."
In the quarter-finals on Friday he will meet Carlos Berlocq of Argentina - the world No 78.