Novak Djokovic Says no Talks on Retaining Boris Becker

World number one Novak Djokovic said he hadn't made any plans to keep Boris Becker as a coach next year as they appeared headed for a split on Thursday.

Djokovic, speaking after cruising into the Shanghai Masters quarter-finals, said he had only made arrangements with the German great for the rest of the season.

"We are still working (together), yeah... for now the plan is the rest of the season, what's left, indoor tournaments," he said.

Asked what would happen next year, Djokovic said: "We still haven't talked about it."

Becker joined Djokovic's coaching team at the start of 2014, helping him win six Grand Slam titles and put together one of the all-time great seasons last year.

But speculation about their partnership has grown since the Serb suffered a crisis of motivation and a series of injuries since completing a career Grand Slam at the French Open.

Djokovic says he has now taken a fresh mental approach since he lost in Wimbledon's third round and in round one at the Olympics, while also enduring wrist and elbow problems.

"I don't think about any trophies or number ones in the world, rankings, anything like that. It's completely different," he said earlier this week.

Djokovic skipped last week's China Open with a wrist injury but there were few doubts about his form as he dismantled Canadian qualifier Vasek Pospisil 6-4, 6-4 on Thursday.

Racquet tantrum

The defending champion weathered 12 aces and 28 winners from Pospisil, 26, before completing the 79-minute victory with a searing forehand to the corner.

"I was very pleased with the way I played from the first to last point. I don't think I dropped my level at all," Djokovic said.

"Only one game when I dropped my serve in the first set on 4-1. Other than that, I was very pleased with the performance."

Second-ranked Andy Murray, who is gunning for Djokovic's number one crown, was even more impressive as he walloped Lucas Pouille 6-1, 6-3.

Murray didn't face any break points against France's Pouille as, like Djokovic, he raced into the last eight without dropping a set.

America's Jack Sock recovered from losing the first set to love as he beat Milos Raonic 0-6, 6-4, 7-6 (10/8), ending a run of eight straight defeats to the Canadian fifth seed.

And Jo-Wilfried Tsonga ousted racquet-smashing teenager Alexander Zverev, denying the young German a potential match-up with his elder brother, Mischa.

Zverev, 19, pushed the ninth seed all the way until he was broken for 5-6 in the third set, prompting a furious racquet-battering which earned him a warning for unsportsmanlike conduct.

Tsonga, serving for the match, safely negotiated three break points before a spectacular airborne smash set up match point, which he gobbled up to win 6-7 (4/7), 6-2, 7-5.

Zverev's brother Mischa, a decade older at 29, also went three sets against Marcel Granollers of Spain but he won 6-7 (4/7), 6-4, 6-1 to set up a meeting with Djokovic.

The Zverevs were the first brothers since Olivier and Christophe Rochus at Miami 2006 to reach the last 16 of a Masters tournament, and were on course to meet in the semis.