Juan Martin del Potro secured his quarter-final spot at the ATP Beijing Open ©ATP/Twitter

Top men's seed Juan Martin del Potro is through to the quarter-finals of the Beijing Open after defeating Russia's Karen Khachanov in straight sets while Caroline Wozniacki has gone through to the last-16 of the women's tournament. 

Argentinian Del Potro was pushed to a tie-break in the second set but triumphed to set up his next match with Serbia's Filip Krajinovic.

The match lasted one hour and 38 minutes and finished 6-4, 7-6 to Del Potro.

With the win, Del Potro qualifies for the season-ending World Tour Finals for the first time since 2013.

The season's finale event will be held at The O2 in London from November 11 to 18.

Krajinovic earned his quarter-final place after his victory over Feliciano Lopez.

He prevailed 7-6, 6-3 against the Spaniard.

The Serbian world number 36 will have to be on his mettle to challenge the world number four as he has never beaten Del Potro before.

Great Britain’s Kyle Edmund is also through to the quarter-finals.

The fifth seed advanced after a tight match against Italy's Matteo Berrettini, which lasted two hours and 48 minutes.

Edmund saved six out of seven break points throughout the match to win, 7-5, 6-7, 7-5.

His quarter-final opponent will be Dusan Lajovic of Serbia who secured his place after beating Grigor Dimitrov.

The Bulgarian third seed is out in less than two hours as Lajovic took the first and third sets to progress.

World number eight Dimitrov served nine double faults throughout the match whilst the world number 55 produced the upset with the game finishing, 6-4, 2-6, 6-4.

In the women's event Wozniacki advanced to the last 16, beating Croatia's Petra Martic in straight sets.

The Danish player won 7-5, 6-3 and will play Estonia's Anett Kontaveit next.

Wozniacki is now the highest ranked player left in the competition after Simona Halep retired through injury earlier on.

Anastasija Sevastova also progressed to the quarter finals by defeating Croatia's Donna Vekic.

The Latvian triumphed 6-3, 6-2 and sets up a quarter-final match-up with Dominika Cibulkova of Slovakia.

Cibulkova is the world number 30 but managed to overcome world number nine, Sloane Stephens.

The American started well, taking the first set, but could not stop the momentum of Cibulkova in the second and third sets.

The Slovakian won 4-6, 6-2, 6-3.