Nick Kyrgios has atoned for the worst performance of his career to storm into the quarter-finals of the China Open in Beijing.

Kyrgios recovered from a loose start to see off German serve-volleyer Mischa Zverev 3-6 6-2 6-2 in their second-round clash on Wednesday.

It was against Zverev last year that Kyrgios infamously tanked at the Shanghai Masters, drawing widespread condemnation from the tennis world and an eight-week ban from the ATP Tour.

The suspension was reduced to three weeks after Kyrgios agreed to undergo counselling.

Tennis Channel commentators again wondered “how dialled in” Kyrgios was in the return bout 12 months on as the mercurial youngster yawned his way through the opening set.

He received a code violation for smashing his racquet in disgust after gifting the German a one-set advantage.

But, looking disinterested, Kyrgios shouldn’t have been surprised to be behind early.

Seemingly in second gear, he barely even bothered to sit down at one changeover, rushing to the other end of the court instead to casually hit balls to himself against the back board.

Other times he sang at the changeover as he slouched in his chair like he was ready for an afternoon snooze.

“It doesn’t look like he’s in the mood to be focused today,” one commentator said.

Tweener-ing into Tuesday like…#ChinaOpen @NickKyrgios pic.twitter.com/joDsO7hBAX

— Tennis TV (@TennisTV) October 3, 2017

But the tennis enigma emerged from his slumber to race through the second set with two service breaks and maintained the intensity to roar ahead 3-0 in the decider.

Facing a rankings dip if he lost after winning the Japan Open during the corresponding week last year, Kyrgios refused to let-up after seizing control.

The NBA lover brought up match point with a slam dunk-style smash and finished Zverev off with a ferocious off-forehand winner to advance after one hour and 22 minutes.

In progressing to his sixth quarter-final of the year, Kyrgios hammered 11 aces and dropped only three points on serve in a dominant deciding set.

Kyrgios next faces either Belgian Steve Darcis or Serbian qualifier Dusan Lajovic for a spot in the semi-finals, where Zverev’s second-seeded brother Alexander could be waiting.

Ostapenko downs Stosur at China Open

Meanwhile, French Open champion Jelena Ostapenko has ended Samantha Stosur’s China Open campaign with a straight-sets second-round win.

In a fluctuating affair, Ostapenko dropped serve four times but broke Stosur on seven occasions to eliminate the Australian 6-3 7-5 in one hour and 48 minutes.

Victory secured the Latvian a spot at the eight-player WTA Championships in Singapore later this month.

-AAP