Grigor Dimitrov withstood a tough test against Dusan Lajovic to rack up a landmark 200th career win on the ATP Tour and book a place in the Chengdu Open quarter-finals on Wednesday.

The Bulgarian has shown signs of returning to top form since linking up with new coach Dani Vallverdu earlier this year and the third seed was a 7-6 (7-1) 6-4 victor over Lajovic in China.

Dimitrov, who won 77 per cent of points on his own serve, said after the round-two win: "It's nice to start a tournament with a win like that. Dusan is a good player.

"I was playing some really good tennis. My main goal was to come out and go for my shots."

Up next for Dimitrov is Diego Schwartzman who accounted for eighth seed Paolo Lorenzi 6-0 6-4, but Argentine compatriot Juan Monaco suffered a 6-3 7-5 loss at the hands of fourth seed Feliciano Lopez.

Karen Khachanov rallied from a set down to defeat Adrian Mannarino, while in round one Marcos Baghdatis was taken the distance in his victory over Pablo Carreno Busta. Viktor Troicki, Albert Ramos-Vinolas and Wu Di also progressed to round two.

At the Shenzhen Open, third seed Richard Gasquet battered qualifier Andrew Whittington 6-1 6-0 in just 51 minutes in round two and will next face Mischa Zverev, who reached an ATP quarter for the first time by upsetting seventh seed Fabio Fognini in straight sets.

Second seed David Goffin also suffered a surprise second-round exit after going down in three sets to Malek Jaziri, while Benoit Paire made it a trio of beaten seeds as he was toppled by Janko Tipsarevic in three sets.

Thomas Fabbiano came from behind to beat Yoshihito Nishioka in their first-round encounter.