Canadian teen Marina Stakusic upsets top seed to reach quarterfinals at Guadalajara Open

Canada's Marina Stakusic is moving on to the quarterfinals of the Guadalajara Open in Mexico.

The Mississauga, Ont., native defeated the tournament top seed, Jelena Ostapenko of Latvia, 6-3, 5-7, 7-6 (0) in the round of 16 on Thursday.

Stakusic faced a 0-4 deficit in the third and final set before rallying to victory.

The 19-year-old won five of the next six games to even it up before exchanging games to force a tiebreaker, where Stakusic took complete control to win the match.

Stakusic had five aces with 17 double faults in the three-hour, four-minute match.

However, she converted eight of her 18 break-point opportunities to help her reach the first WTA quarterfinal match of her career.

WATCH | Stakusic advances to her 1st-ever WTA quarterfinal:

Stakusic was a key part of Canada's Billie Jean King Cup-winning team last fall, delivering three key victories, including a stunning upset of 43rd-ranked Martina Trevisan in the final against Italy.