Elena Rybakina reaches Montreal semifinals after injured Marta Kostyuk retires in second set

MONTREAL (AP) — Elena Rybakina advanced to the National Bank Open semifinals after Marta Kostyuk was forced to retire with an apparent arm injury Monday with Rybakina leading 6-1, 2-1.

Rybakina, the No. 9 seed from Kazakhstan, converted three of her 10 break-point chances in the quarterfinal matchup at IGA Stadium. The players shook hands at the 54-minute mark before the 24th-seeded Kostyuk exited the court in tears.

After the third game, the Ukrainian's trainers wrapped her forearm in medical tape.

Rybakina will face the winner of Monday night's matchup between Canadian teen sensation Victoria Mboko and Jessica Bouzas Maneiro of Spain.

Mboko upset top-seeded Coco Gauff in straight sets Saturday, winning the lopsided match in just 62 minutes.

The 18-year-old from Toronto has surged from outside the top 300 to No. 85 in the WTA rankings in a breakthrough year.

The tournament final is Thursday. The event's top-five seeds were eliminated before the quarterfinals.