Roddick dominated Ito with a powerful serve and ended the match in Ariake Colosseum with his eighth ace.

“It felt like a match coming off a long layoff,” said Roddick, who lost in the second round of the US Open on Sept. 1. “There were some good things, some inconsistent things. Since New York, I’ve been trying to get in physical shape and I’ve been able to do that.”

Roddick will face Jeremy Chardy, a 6-3, 7-6 (2) winner over Edouard Roger-Vasselin.

Defending champion Jo-Wilfried Tsonga lost to Jarkko Nieminen of Finland 6-4, 5-7, 6-1 in his first match since June 30. Top-ranked Rafael Nadal downed Colombian Santiago Giraldo 6-4, 6-4 to reach the second round.

Tsonga tore his left knee patella in a Wimbledon quarterfinals loss to Andy Murray and missed the US Open and France’s wins in the Davis Cup quarterfinals and semifinals.

The 12th-ranked Tsonga looked impressive at times in the first-round match, firing 14 aces. But Nieminen, coming off the Thailand Open final last weekend, served consistently better.

“I did all I could but it was not enough,” Tsonga said. “It was tough, my first match in three months, and Jarkko played well. But I have no pain in my knee, so that is positive.”

Nadal, coming off a surprise loss in the semifinals of the Thailand Open on Saturday, had to work hard for the victory in his Japan debut.

“I started a few games love-30,” Nadal said. “He played well. He was very aggressive. My serve was the worst it has been in the last 10 or 11 games and I was a little more tired than usual and not focused on every point.”

Nadal will face qualifier Milos Raonic, who had 22 aces in a win against Florent Serra 6-4, 3-6, 6-4.

“I lost against him in doubles in Toronto,” Nadal said. “He can play very well from the baseline and has a good serve so I have to be aggressive against him.”

Guillermo Garcia-Lopez defeated Rajeev Ram of the United States 6-7 (3), 6-4, 7-6 (1). They each served 17 aces.

Also, fourth-seeded Jurgen Melzer defeated Juan Monaco 6-4, 4-6, 6-1, and No. 5 Gael Monfils beat wildcard Go Saeda 7-6 (10), 6-4. No. 8 Michael Llodra lost to Marco Chiudinelli 6-3, 6-0.

Other winners included Richard Gasquet, Viktor Troicki and Andreas Seppi.

Djokovic, Murray advance at China Open

In Beijing, top-seeded Novak Djokovic opened defense of his China Open title on Tuesday with a 6-1, 6-3 win over Gong Maoxin.

Djokovic, ranked No. 2 after a runner-up finish at the US Open, won 87 percent on his first serve points.

Second-seeded Andy Murray defeated Paul-Henri Mathieu 6-2, 6-3, and third-seeded Robin Soderling dropped the first set before rallying past Tommy Robredo 4-6, 6-1, 6-4.

Murray served up 10 aces to beat Mathieu, once ranked as high 12th. He had to qualify for the main draw after a series of injuries.

In other first round matches, Alexandr Dolgopolov beat Marcos Baghdatis 6-4, 6-4, and Nicolas Almagro defeated Lukasz Kubot 7-5, 6-2. Fourth-seeded Nikolay Davydenko defeated Florian Mayer 6-3, 6-4.

In the second round of women’s singles, Maria Sharapova made 18 unforced errors in losing to Elena Vesnina 7-6 (3), 6-2. Sharapova lost in the opening round in Tokyo last week.

Li Na defeated Alisa Kleybanova of Russia 6-1, 6-4, and 14th-ranked Shahar Peer beat Patty Schnyder 6-4, 6-2. Petra Kvitova defeated Kaia Kanepi 7-5, 6-7, 6-2.