Shanghai, Oct 11 (IANS/RIA Novosti): Novak Djokovic reached the quarter-finals of the Shanghai Masters here Thursday after beating Spain's Feliciano Lopez in straight sets.

The players spent a little over an hour on the court before the World No.2 sealed a 6-3, 6-3 win.

The Serbian next faces either compatriot Janko Tipsarevic, seeded six, or German veteran Tommy Haas.

Meanwhile, fourth seed Tomas Berdych had to dig deep to defeat World No.22 Sam Querrey of the United States.

The Czech secured a tough 6-2, 6-7(3), 6-4 victory to book a quarterfinal encounter with fifth seed Jo-Wilfried Tsonga.

Tsonga had hit 11 aces to eliminate Marcos Baghdatis of Cyprus 6-2, 7-6(2).

"I feel like I am playing really good," Tsonga said after the match.

"It's only now I started to play well so I hope I will continue to play like this. After all, of course for me London is a goal."

London will host the ATP World Tour Finals from Nov 5-12.

Tsonga is in a tussle with Tipsarevic for the eighth and final spot at the season finale.