Novak rolls on, Fed falls

Novak Djokovic kept his win streak alive at the Paris Masters on Thursday, but there was defeat for Roger Federer at the hands of big-serving American John Isner.

Rafael Nadal and Andy Murray also reached the quarterfinals, but in contrasting styles.

World number one and defending champion Djokovic went through to the last eight in the final tournament of the ATP's regular season with a 6-3, 7-5 victory over Gilles Simon that took his unbeaten run to 19 matches.

Djokovic will next play fifth seed Tomas Berdych of the Czech Republic who eased past an injury-hampered Jo-Wilfried Tsonga 6-3, 6-4 for a place in the semifinals of a tournament he has won three times previously, including the last two years

Federer was shocked to find himself leaving for home without once having dropped his serve as Isner typically won on two tie-breaks 7-6 (7/3), 3-6, 7-6 (7/5), hammering down 27 aces in the process.

Isner will play David Ferrer for a semifinal spot after the Spanish eighth seed outlasted Grigor Dimitrov of Bulgaria 6-7 (4/7), 6-1, 6-4.