A frustrated Andy Roddick dug deep to beat Taiwan's Lu Yen-hsun 6-2, 3-6, 6-2 at the Shanghai Masters on Monday and avoid a second ignominious first-round exit in a week in China.

The American 10th seed, who lost to Lu at Wimbledon last year in their most recent meeting, started the match in blistering form, breaking twice and racing into a 4-0 lead, taking the first set 6-2.

But the Taiwanese world number 74 hit back strongly in the second set, striking a stunning two-handed backhand down the line to force a break for a 3-1 lead, which proved enough to level the match against an erratic Roddick.

Clearly unsettled, the American voiced his frustration at noise and movement in the sparse crowd and at a ball-boy, but he refocused and crucially broke in the fourth game of the decider.

Roddick, ousted from the first round of the Beijing Open by South Africa's Kevin Anderson last week, kept his grip as the Lu challenge faded, breaking again to seal the match in a little under two hours.

"He plays so high risk. You know, a lot of it's two sets with two breaks, one set where I had more break opportunities and didn't get it," said Roddick.

"You know, overall I thought it was pretty good, save four games maybe."

The American former world number one said it has been "the toughest year I've had.

"I feel like I've been starting and stopping a lot. You know, I'm going to probably have to adjust how I go about things a little bit more," he added.

"I think the frustrating thing is a lot of times, when I've done the work, I haven't felt terrible about my tennis, but I've been unprepared a lot of the time this year," he said.

Earlier, former world number three David Nalbandian eased into the second round, beating Latvia's Ernests Gulbis 7-5, 6-4.

Nalbandian, a member of the Argentinian team that beat Novak Djokovic's Serbia in last month's Davis Cup semi-finals, has slipped to 57th in the world rankings after an injury-plagued season.

But the 29-year-old was too good for his higher-ranked opponent, breaking Gulbis (ranked 51) twice in the first set and then once more in the second set to seal the win.

Wimbledon quarterfinalist Bernard Tomic beat Kevin Anderson 7-6 (7/5), 6-7 (4/7), 6-3 in a match dominated by serve, with Australia's Tomic forcing the only break of the contest in the decider.

"I'm happy I won against a player like Kevin because he can beat so many world class players on his day," said Tomic, who achieved a career-high ranking of 49 on Monday.

"I was happy to break him in that third and I think that's what won the match," he added.