No. 19 seed Madison Keys scored the big upset on Day 9 of the Australian Open, defeating No. 6 Elena Rybakina 6-3, 1-6, 6-3 at Margaret Court Arena to advance to the tournament quarterfinals.

The No. 6 seed missed multiple break points to seize the advantage in the third set and Keys profited to move into the quarterfinals.

American Madison Keys upset sixth seed Elena Rybakina 6-3 1-6 6-3 in a roller-coaster match at Margaret Court Arena to march into the quarter-finals of the Australian Open on Monday and extend her win streak to nine matches this year.

Madison Keys recalled a couple of tough Australian Open losses, including one to the legendary Serena Williams, shortly after returning to the Slam’s quarterfinals on Monday.

Elena Rybakina, the sixth seed at Melbourne Park, had looked in fine form in the early rounds, but came into Monday's clash with Madison Keys at Margaret Court Arena carrying a back issue

But it was her return game that did the loudest talking Monday in an Australian Open battle featuring two of the WTA’s most fearless ball-strikers. Taking on sixth seed Elena Rybakina, Keys surged ahead for a 6-3, 1-6, 6-3 victory.

In the Australian Open Round of 16 on Sunday, No. 7-ranked Elena Rybakina takes on No. 14 Madison Keys.Rybakina secured a two-set victory over Dayana Yastremska (6-3, 6-4) in the Round of 32 in

She will next play Ukraine's Elina Svitolina, who beat Veronika Kudermetova 6-4, 6-1 earlier on Jan 20. Read more at straitstimes.com.

Madison Keys has positioned herself among the top-5 active players with the most main-draw wins in Grand Slam tournaments after an impressive Australian Open campaign. The World No. 14 secured her

Rock Island's Madison Key is one of the last eight players still alive at the Australian Open, the first tennis Grand Slam of the year.

The Australian Open semi-final line-up will be confirmed at the close of play on day 11 and bookmakers expect defending men's champion Jannik Sinner to seal his place in the final four with victory over home favourite Alex de Minaur.