Milos Raonic has to work hard to reach Delray Beach Open semi-finals

The world number four, top seed in the tournament, had to come from a set down to beat Britain's Kyle Edmund, eventually triumphing 4-6 6-3 6-4.

That victory sets up a mouth-watering semi-final date with Juan Martin del Potro after the Argentinian continued his comeback from injury with a 7-5 7-5 win over Sam Querrey.

Jack Sock booked an all-American semi-final with Donald Young after progressing past another home favourite Steve Johnson 6-4 7-6 (7/4).

Defending champion Nick Kyrgios eased into the semi-finals of the Open 13 Marseille with a 6-3 6-3 win over Slovakian qualifier Norbert Gombos.

It was on the south coast of France 12 months ago that Kyrgios won his first ATP World Tour title and it took the 21-year-old Australian just 58 minutes to book his place in the last-four again this year as a ruthless display of serving, which included 15 aces, meant he lost just six points on serve.

He will face Frenchman Jo-Wilfried Tsonga, who thumped compatriot Gilles Simon 6-4 6-1, in the quarter-finals.

"I thought I served and returned really well today," Kyrgios told atpworldtour.com. " All that matters is that I'm going out there and playing every point hard.

"I think I'm pretty aggressive on my returns, particularly here where I'm trying to get in the first big hit."

Tsonga, who won in Rotterdam last week, came out on top in the battle between two twice former champions thanks in main to converting four of seven break points.

A second all-French quarter-final saw Richard Gasquet rally from a set down to overcome Gael Monfils 6-7 (5/7) 6-4 6-2.

Gasquet will face another compatriot in the last four after Lucas Pouille fired down 15 aces in a 4-6 6-1 6-4 comeback win against Russian Daniil Medvedev.

Casper Ruud's dream week at the Rio Open continues as he earned a semi-final meeting with Pablo Carreno Busta.

The young Norwegian had not won a game on the ATP Tour before this week but suddenly finds himself in the last four following a 6-2 7-6 (7/2) success over Thiago Monteiro.

Carreno Busta awaits after the Spaniard beat Alexandr Dolgopolov 7-6 (7/4) 6-7 (7/2) 1-0, with the Ukrainian retiring due to injury.

Dominic Thiem, the second seed, will meet Albert Ramos-Vinolas in the last four after both men beat Argentine opponents.

Thiem breezed past Diego Schwartzman 6-2 6-3 while the Spaniard beat Nicolas Kicker 6-2 6-3.