ROTTERDAM, Netherlands (AFP) — Australian Open champion Jannik Sinner reached the Rotterdam semifinals on Friday when injury-plagued Milos Raonic was forced to retire at 1-1 in the second set of their Last Eight clash.

Top seed Sinner took the first set 7-6 (7/4) before the big-hitting 33-year-old Canadian called it quits after two more games.

Sinner goes on to face Dutchman Tallon Griekspoor, who defeated Emil Ruusuvuori of Finland, 7-5, 7-6 (7/4) for a place in Sunday's final.

"Obviously, this is not the way you want to win the match," Sinner said.

"I wish him a speedy recovery. I was actually playing and I was not realizing that he was about to retire but he knows his body really well and he knows his limits so, for sure, it's the right choice for him."

Sinner, 22, can take the world No. 3 ranking if he wins the title on Sunday. If that happens, he would become the highest-ever ranked Italian man.

Raonic saw two set points come and go in the opener on Friday before he retired as the 2016 Wimbledon runner-up endured another injury nightmare.

The former world No. 3 has slumped to 309 in the rankings after missing two years of action due to a combination of back, ankle and knee injuries.

Earlier Friday, Bulgarian sixth-seed Grigor Dimitrov edged into the semi-finals, seeing off a determined challenge from Kazakhstan's Alexander Shevchenko 7-6 (7/2), 3-6, 6-4.

Dimitrov will face fifth seed Alex De Minaur after the Australian shocked second seed Andrey Rublev 7-6 (7/5), 4-6, 6-3.

World No. 13 Dimitrov seemed unhappy with his performance, admitting he struggled to read the Shevchenko service.

"The way he was serving was just incredible. For some reason I was not really able to find my angles. He was not giving me any time to develop my game," Dimitrov said.

"Today was just one of those matches because I was not at my best. Hopefully I can raise my game" for Saturday's semifinal.