Novak Djokovic fired an ominous warning to his rivals yesterday, powering into the Shanghai Masters quarter-finals as defending champion Andy Murray finally made his bow with an easy win.

The Serbian second seed, looking to wrestle the world No1 ranking from rival Roger Federer, barely broke a sweat against Spain's Feliciano Lopez, wrapping up a straightforward 6-3, 6-3 victory.

In-form Djokovic, fresh from his third China Open title in Beijing on Monday, struck 12 aces and took advantage of some below-par serving by the left-handed Lopez, breaking him three times.

A powerful backhand down the line sealed the match for the 25-year-old and set up a clash against either sixth seed Janko Tipsarevic of Serbia or German veteran Tommy Haas.


"I'm not very well known around the Tour for big serving," said Djokovic. "But so far in this tournament, and also in Beijing, it has been working very well for me."

US Open champion Murray, 25, proved far too strong for Ukraine's Alexandr Dolgopolov, serving consistently well and seizing on five out of six break points to win 6-2, 6-2 in 57 minutes.

It was the first match of the tournament for the Scot. The top eight seeds received a first round bye.

Earlier, fifth seed Jo-Wilfried Tsonga struck 11 aces in seeing off the challenge of former Australian Open finalist Marcos Baghdatis of Cyprus 6-2, 7-6 (7-2).

Czech fourth seed Tomas Berdych set up a quarter-final meeting with Tsonga after beating American Sam Querrey 6-2, 6-7 (3-7), 6-4.

Radek Stepanek of the Czech Republic upset eighth seed John Isner of the United States 6-4, 6-7 (5-7), 6-3.