Rafael Nadal started his bid to win a fifth title this year with a 6-3 6-4 victory over world number 37 Benoit Paire at the Madrid Open.
The Spaniard, who returned from a knee injury in February, broke his French opponent once in each set to seal his place in the third round.
The fifth seed will meet compatriot Nicolas Almagro or Russian Mikhail Youzhny for a place in the last eight.
The 26-year-old is looking to win the tournament for a third time.
"I'm taking things day by day and don't know if I'm in perfect shape or not," said Nadal, who could meet Roger Federer in the semi-finals.
"The important thing is that I am here in Madrid competing again after seven months out injured," added the 11-time Grand Slam winner.
Nadal was given a code violation at 4-2 in the first set for taking too long to prepare himself between points at deuce, but went on to take the set.
The Frenchman had his only break point of the match with Nadal serving at 1-2 in the second, but the Spaniard retrieved a Paire smash and the 23-year-old could not control his resulting volley at the net.
Nadal increased the pressure on the Paire serve and broke through at 4-4 before serving out.
had to come back from a set down to get past Poland's Jerzy Janowicz 6-7 6-3 6-2 while seventh seed
is set to return to action on Thursday, when he takes on France's Gilles Simon.
World number one Novak Djokovic was beaten by Grigor Dimitrov on Tuesday.