RIO DE JANEIRO (AP) — White tape peeking out from under the red sweat band on his injured left wrist, Rafael Nadal was back in action Sunday, playing his first match in 2½ months.

And he was back at an Olympics for the first time in eight years.

He was not, Nadal insisted after a 6-2, 6-1 victory over Argentina's Federico Delbonis at the Rio de Janeiro Games, back at full strength, however. And he will not, he also insisted, discuss the problematic tendon sheath in his racket-wielding arm for the rest of the event.

"My wrist is not perfect. My wrist needs more time," the Spaniard said. "If it was a 'normal' tournament on the circuit, I wouldn't be here. My wrist is not perfect. It isn't 100 percent."

Nadal won a gold medal in singles at the 2008 Beijing Games, but he missed the 2012 London Olympics because of a knee injury that also forced him out of the U.S. Open later that season.

"There's only one chance every four years to experience an Olympic Games. It's something unforgettable," said Nadal, who carried Spain's flag during the opening ceremony. "I missed the last one in London, so I didn't want to miss this one."

As a former No. 1-ranked player and a 14-time Grand Slam champion, Nadal is one of his sport's central figures, so his health is a significant topic in tennis. It was also the most noteworthy subject on a wind-swept, star-studded second afternoon of competition in Brazil that included straight-set wins by 2012 singles gold medalists Serena Williams and Andy Murray; top-seeded Novak Djokovic was scheduled to face Juan Martin del Potro at night.

During Williams' uneven 6-4, 6-2 elimination of Australia's Daria Gavrilova in the main stadium, winds that reached 25 mph caused delays of about 2 hours on the eight smaller courts. Murray beat Serbia's Viktor Troicki 6-3, 6-2 in less than 1½ hours.

Neither Williams nor Murray had played since winning Wimbledon titles a month ago, and both were in doubles action later Sunday alongside older siblings: Williams with her sister Venus; Murray with his brother Jamie.

Sunday's contest was Nadal's first since he surprisingly showed up at a news conference at the French Open wearing a blue brace on his left wrist and announced he would be withdrawing from the clay-court tournament he has won a record nine times.

A question about the wrist arrived early in the English portion of his post-match session with reporters Sunday, and when the Spanish portion began with a query about the same topic, Nadal's response started with a smile and these words: "I said it in English, and I'll say it again in Spanish."

He made clear both times that he didn't want to address the subject the rest of the way in Rio.

Nadal appeared a tad tentative in the early going against Delbonis, a fellow left-hander who is ranked 43rd, but eventually displayed confidence with his heavy-topspin forehand, producing half of his 14 winners with that stroke.

Along the way to breaking for a 3-2 lead, Nadal smacked one down-the-line forehand winner, then threw a big uppercut and yelled, "Vamos" — eliciting a loud roar from spectators. There was a nearly identical celebration, and crowd reaction, when the match concluded.

Nadal played cleanly, making only 15 unforced errors, while Delbonis made 31.

Indeed, the one thing that truly bothered the third-seeded Nadal on this day (aside, perhaps, from the wrist questions) was the on-court signage behind the baselines. At one end is a scoreboard, near the other is a serve-speed readout, and it contains a few shades of green and yellow, which Nadal complained made it tough to see the yellow tennis balls during the course of play.

He said the International Tennis Federation needed to make sure the setup was better, because "you can't play when you're losing sight of the ball."

ITF spokesman Nick Imison said tournament organizers would look into Nadal's comments.