Top seed Aslan Karatsev exited the Astana Open at the last-16 stage with a straight-sets defeat to Emil Ruusuvuori on Thursday.

World number 84 Ruusuvuori saved a set point in the first-set tie-break on his way to a 7-6 (8-6) 6-4 victory and will now face Ilya Ivashka for a place in the semi-finals.

There was nearly another upset as home hopeful Alexander Bublik, seeded second, had to recover from a set down to overcome Miomir Kecmanovic 2-6 6-3 7-5.

Carlos Taberner awaits Bublik in the next round after the Spaniard beat Egor Gerasimov 5-7 7-6(5) 7-5.

Kwon Soon-woo and James Duckworth saw off Dusan Lajovic and Filip Krajinovic respectively in straight sets to remain a course for glory.

At the Moselle Open in Metz, meanwhile, Gael Monfils took out Philipp Kohlschreiber 7-6(2) 6-4 to reach the quarter-finals on home soil.

Tournament favourite Hubert Hurkacz made light work of 2016 champion Lucas Pouille with a 6-2 6-3 victory to set up a meeting with Andy Murray in the quarter-finals.

Elsewhere on Thursday, German qualifier Peter Gojowczyk proved too strong for Karen Khachanov and will now face Marcos Giron, who upset fourth seed Alex de Minaur.

Top seed Milos Raonic saw his stay at the Atlanta Open come to an early end with a three-set defeat to American Brandon Nakashima on Wednesday. 

The 19-year-old Californian Nakashima, ranked 115th in the world, prevailed 5-7 6-3 7-6 (7-4) over world number 22 Raonic in their first meeting. 

The big-serving Canadian had 10 double faults to go with his 27 aces, while Nakashima did not commit one double fault and managed 13 aces. 

It was the latest in a string of recent wins over established players for Nakashima, who stunned Sam Querrey and John Isner last week at Los Cabos before falling to Cameron Norrie in the final. 

Nakashima next faces Australia's Jordan Thompson, who beat Peter Gojowczyk of Germany 7-6 (8-6) 6-4 to reach the quarter-finals. 

In the other half of the draw, fifth seed Taylor Fritz rallied to defeat fellow American Steve Johnson 6-7 (5-7) 6-4 6-1 in a rematch of a quarter-final at Los Cabos, also won by Fritz. 

Fritz will face countryman Reilly Opelka, who outlasted Bjorn Fratangelo 7-6 (7-3) 7-6 (7-4). The 6-foot-11 Opelka pounded 25 aces to just three double faults, winning 84 per cent of his service points.