Olympic champion Belinda Bencic is into the final of Berlin's WTA grass-court tournament after fighting back to see off second seed Maria Sakkari following a three-hour tussle in sweltering conditions.

Bencic rallied from losing the hard-fought first set, which lasted 76 minutes, to secure a 6-7 (6/8), 6-4, 6-4 win in temperatures of around 33 degrees Celsius (91 degrees Fahrenheit). 

Bencic, who won the singles Olympic title in Tokyo last year, will face either top seed Ons Jabeur of Tunisia or American teenager Coco Gauff in Sunday's final.