SHANGHAI — Nick Kyrgios looked completely disengaged at the Shanghai Masters, like he couldn't get off the court fast enough. Rafael Nadal fought as hard as he could to prolong his stay in China but came up short.

Both players lost in the second round on Wednesday, though the effort they put forth couldn't have been more different.

Kyrgios was booed by the crowd and admonished by the chair umpire for his lack of professionalism during a 6-3, 6-1 loss to German qualifier Mischa Zverev. The Australian floated in 67 mph (108 kph) first serves, went for aces on his second serves, and argued with a fan.

Afterward, he defended his behaviour by saying he didn't owe the spectators anything and fans could "just leave" if they didn't like his attitude.

Nadal's late-season struggles continued as he fell to Viktor Troicki 6-3, 7-6 (3). The result prompted the Spaniard to contemplate shutting his season down early.

Also, Andy Murray reached the third round by beating Steve Johnson 6-3, 6-2. U.S. Open champion Stan Wawrinka and Milos Raonic also advanced in straight sets.

Kyrgios, seeded 12th, arrived in Shanghai as one of the most in-form players in the draw after winning his third title of the season at last week's Japan Open. But all the matches seemed to catch up to him against Zverev, a player ranked 110th in the world who had only won seven ATP Tour matches all season.

At one point in the first set, Kyrgios tapped a soft serve over the net and started walking toward his chair before Zverev had even returned the ball, drawing a rebuke from the chair umpire during the changeover.

"This is a professional tournament," Ali Nili said. "You have to act like a professional."

Toward the end of the 48-minute match, the crowd started booing and jeering. One man yelled, "Respect the game," prompting a furious Kyrgios to shout: "You want to come here and play?"

Asked afterward if he thought he owed the spectators a better effort, he turned defiant again.

"What does that even mean? I'm good at hitting a tennis ball at the net. Big deal. I don't owe them anything," he said. "If you don't like it, I didn't ask you to come watch. Just leave."

Kyrgios added that he is so tired from the lengthy season, he wasn't interested in chasing one of the last spots for the ATP finals next month, either.

"I couldn't care less, to be completely honest with you," he said.

He later sounded apologetic on Twitter, saying, "Not good enough today on many levels, I'm better than that. I can go on about excuses but there are none. Sorry."

Murray said after his match that he understands how Kyrgios might have been feeling, but he still should have given his best effort.

"If he didn't do that, then he will be disappointed with himself tonight," he said. "But we're not perfect. Everyone makes mistakes."

Nadal also has a chance to clinch a spot in the ATP finals - he currently sits in seventh position for the eight-man field - but he was unsure at this point if he wanted to prolong his season.

"I cannot say now what I'm going (to) do during the next month," he said. "Sometimes (to) keep competing is not the solution. Sometimes the solution is practice ... and have a process of training. And maybe that's an opportunity to do it."

The fourth-seeded Nadal struggled to create depth and pace with his forehand, a problem he attributed to the wrist injury that sidelined him for part of the season.

His goal now is to be back in peak condition for the Australian Open at the start of the new year.

"I have two months and a half to put myself at the level that I need to be," Nadal said, "and I have the confidence that I'm going to do it."

Other winners included 11th-seeded David Goffin, 13th-seeded Lucas Pouille, Jack Sock and Vasek Pospisil. Seventh-seeded Tomas Berdych lost to Marcel Granollers.