The Halle Open suffered two major exits on Wednesday, with both Kei Nishikori and Dominic Thiem suffering surprise second-round defeats.
Nishikori looked totally out of sorts against Karen Khachanov, going down 6-2, 6-2 in one hour and 18 minutes.
The Russian was in total control of the contest, converting four of 11 break points and saving the only break point against him.
For Nishikori, it was a bad case of deja vu, as Khachanov also beat him in the second round in Halle last year.
"I made too many unforced errors, I had a lot of mistakes," he said.
"He was playing good, but nothing special, I couldn't make a first serve and I should have stayed back more at the baseline.
"Khachanov hits a flat ball and that makes it not so easy on grass. I need to train more before Wimbledon."
It was a similar story for Roland Garros finalist Thiem, who found himself outmatched by Japanese World No 2 Yuichi Sugita.
Sugita broke Thiem's serve twice at the top of the first set and never looked back, wrapping up a 6-2, 7-5 victory in one hour and 29 minutes.
World No 1 Roger Federer returns to action on Thursday for his second-round match against Benoit Paire.