Second-seeded Rafa Nadal has not lost serve once in three one-sided victories at the US Open this week but he feels his service game needs improving in his quest for another title at Flushing Meadows.

Nadal might appear to be nitpicking given that his 6-4, 6-3, 6-3 battering of Ivan Dodig of Croatia on Saturday sent him into the fourth round and extended his 2013 hard-court record to 18-0.

But the 27-year-old Spaniard knows what it takes to win Grand Slams and the US Open in particular.

"I didn't feel that I was serving great," said the 12-time major winner and 2010 US Open champion. "I served OK ... not bad.

"At important moments I did a few good serves, but I am winning because I am playing well from the baseline and I am making the right decisions at the right moments."

Nadal, the undisputed King of Clay after winning his eighth French Open earlier this year on the red clay of Roland Garros, continued to show his hard-court prowess as he ran the dogged Dodig relentlessly at Arthur Ashe Stadium.

"I think I played a correct match today; a happy 6-4, 6-3, 6-3 against a player who came to this (stage of the) tournament winning against tough opponents like (Nikolay) Davydenko and (Fernando) Verdasco.

"To be able to win against him in straight sets is great news. I played better today than in the previous matches. That's always a positive thing."

Nadal smacked 37 winners in the two-hour, eight-minute victory, nearly double the number registered by Dodig. And he showed his versatility by winning 14-of-17 forays to the net set up by his ferocious groundstrokes.

Nadal has yet to have his service broken, but he feels that statistic might be deceiving. "It will happen," he said, drawing a laugh from reporters.

He won the 2010 championship thanks in large part to a booming serve that reached speeds over 130 miles an hour (209 kph) after making a subtle grip change.

The Mallorcan is having a remarkable comeback year after being sidelined for seven months with a knee injury, but the power has not been turned on for his first deliveries this week.

While he faced only two break points against Dodig, Nadal had his fastest serve clocked at 123 mph (198 kph), with his average first serve speed 108 (174 kph).

"It's working, but I am not serving at 130 miles every time," said Nadal, who instead is relying on placement and consistency to gain an upper hand on his service points.

"It's working because I am playing well from the baseline. It's working because I am serving with the right percentage. It's working for the first three matches. We'll see if I am able to keep it working."

Nadal's formula has worked in 2013 as he has posted a 56-3 match record including a run to the French Open crown.

(China Daily 09/02/2013 page24)