Marseille, France (SportsNetwork.com) - Ukrainian Sergiy Stakhovsky stunned second seed Stan Wawrinka, while acrobatic French crowd favorite Gael Monfils secured a berth in the final four at the Open 13 tennis event.

Stakhovsky doused last week's Rotterdam champion and last year's Australian Open titlist Wawrinka in 6-4, 3-6, 6-4 fashion on Friday.

The 29-year-old Stakhovsky saved four-of-five break points faced and survived six aces from his Swiss counterpart to win the match in 1 hour, 51 minutes.

Meanwhile, the seventh-seeded former top-10 star Monfils vaulted past Italian Simone Bolelli 6-4, 6-4 on the indoor surface at Marseille's Sports Palace. Bolelli stunned top seed Milos Raonic here on Thursday for his first-ever victory against a top-10 opponent in 36 tries.

Monfils' semifinal opponent on Saturday will be fourth-seeded Spaniard Roberto Bautista Agut, who moved on with a 7-6 (9-7), 6-3 decision against Austrian Dominic Thiem.

The other semi will pit fifth-seeded Frenchman Gilles Simon against Stakhovsky. The 2007 Marseille titlist Simon capped Day 5 by besting fellow countryman Jeremy Chardy 7-5, 7-6 (8-6).

The 2015 Marseille champ will collect $117,000.