Adelaide, Jan 15 : Defending champion Madison Keys suffered a shock exit from the Adelaide International on Thursday, crashing out in the quarter-finals after a three-set defeat to Canadaâ??s rising star Victoria Mboko.

World No. 17 Mboko, 19, defeated ninth-ranked Keys 6-4, 4-6, 6-2 in one hour and 53 minutes for her second career victory against a top-10 opponent.

Eighth seed Mboko struck first by breaking Keys early to take the opening set but struggled to match the Americanâ??s powerful serving in the second. In the deciding set, Mboko was clinical on serve, winning 75 percent of points on her first delivery and capitalising on the only break opportunity she earned.

"I know she won this tournament last year and, of course, the Australian Open. I knew coming into this match it had to be a big fight, so I'm glad I got it done," Mboko said on court after the match, as reported by Xinhua.

Keys had won the Adelaide International title in 2025 before going on to claim her first career Grand Slam title at the Australian Open weeks later. She will be in action in Melbourne on January 18 to defend her title.

Mboko will play Australiaâ??s Kimberly Birrell in Fridayâ??s semifinal, after the world No. 107 came back from a set down to beat Romaniaâ??s Jaqueline Cristian 5-7, 6-1, 7-5 in a three-hour epic.

Birrell led 5-2 in the first set and had five set points but could not make the most of the opportunities as Cristian won five games in a row to seal the set. Birrell flipped the momentum in a dominant second set where she won the opening five games.

Tied at 5-5 in the third set, Birrell got the decisive break of serve for a 6-5 lead and converted her second match point in the following game with a backhand winner down the line, heading to her first career semifinal in a WTA 500 tournament.

Mbokoâ??s rapid rise has been one of the standout stories of the season. She was named WTA Newcomer of the Year after lifting the National Bank Open title in Montreal and climbing from world number 333 at the start of the year to number 18 in the rankings.

/IANS