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NOW: Alexander Zverev beats Carlos Alcaraz 6-1 6-3 6-7 (2-7) 6-4 in men's quarter-finals
German will play Daniil Medvedev, who beat Hubert Hurkacz 7-6 (7-6) 2-6 6-3 5-7 6-4
Qualifier Dayana Yastremska beats Linda Noskova in straight sets to reach first major semi-final
Zheng Qinwen beats Anna Kalinskaya 6-7 (4-7) 6-3 6-1 to reach women's singles semi-finals
Britain's Neal Skupski and American partner Desirae Krawczyk reach mixed doubles final
*Kalinskaya 7-6 (7-4) 3-6 1-5 Zheng
Zheng lets out a roar after burying a forehand and a fine first serve helps her seal the hold.
China's 12th seed is a game away from her first Grand Slam semi-final!
Kalinskaya 7-6 (7-4) 3-6 1-4 Zheng*
Zheng takes her ace tally to 10 in this match - and a tournament-leading 44 this fortnight - with three in succession to take charge on serve from 0-15 down.
But a couple of misses later and Kaliskaya has an opportunity she probably didn't expect to get only moments ago.
Kalinskaya 7-6 (7-4) 3-6 1-4 Zheng*
Zheng Qinwen is waiting at the back of the court. She wants to get on with this, with the semi-finals in her sights.
It looks like Anna Kalinskaya may have a bit of tightness in her hip following two demanding hours on Rod Laver Arena this evening - not to mention the matches that have come before this over the past 10 days.
She's going to be fine to continue, at least.
Kalinskaya 7-6 (7-4) 3-6 1-4 Zheng*
A medical timeout for Anna Kalinskaya, who is getting treatment on her right leg at the side of the court.
Hopefully she'll be able to see this out. It could also give her a bit of thinking time as she attempts to find a route back into this.
Kalinskaya 7-6 (7-4) 3-6 1-4 Zheng*
Zheng Qinwen just has too much for Anna Kalinskaya now. The 12th seed is overpowering and outworking her opponent and she has one foot in the semi-finals as she clinches the double break.
A fourth game in a row leaves her two from victory.
Carlos Alcaraz and Alexander Zverev are beginning their warm-ups.
*Kalinskaya 7-6 (7-4) 3-6 1-3 Zheng
Zheng, oozing confidence now, carefully watches an overhead and smashes the ball in for 30-30 on her opponent's serve.
Is she going to finish this off right here?
Kalinskaya yields under pressure. Break point.
*Kalinskaya 7-6 (7-4) 3-6 1-3 Zheng
Zheng is on a roll now, at the perfect moment too.
She backs up the break to love with a love hold, making it 12 points without response as she threatens to run away with this match.
Has Kalinskaya got anything left?
Kalinskaya 7-6 (7-4) 3-6 1-2 Zheng*
Zheng Qinwen makes the breakthrough in the deciding set!
A backhand winner clinches the break at the end of a messy game by Anna Kalinskaya.
How costly could that prove to be? She has time to get herself back into this, but with the 12th seed hitting her stride it's certainly not going to be easy.
*Kalinskaya 7-6 (7-4) 3-6 1-1 Zheng
Kalinskaya finds herself in a tight spot at 0-30 and a miss on the backhand hands over three break points.
*Kalinskaya 7-6 (7-4) 3-6 1-1 Zheng
Are you backing the 12th seed or the underdog from here?
You sense, as proved the case in the second set, a single break could be enough for either player to take this decider. One lapse in concentration is all it takes.
Zheng holds with in her opening service game as we approach the two-hour mark.
Kalinskaya 7-6 (7-4) 3-6 1-0 Zheng*
Anna Kalinskaya twice gets herself to game point, and she manages to hold on at the second attempt as Zheng Qinwen drifts long.
*Kalinskaya 7-6 (7-4) 3-6 Zheng
A clean backhand winner gets Anna Kalinskaya on the board after a double fault first up.
That's nice from Zheng Qinwen, though, popping over a forehand despite being stretched into the corner, and she wrestles herself to deuce with another winner.
*Kalinskaya 7-6 (7-4) 3-6 Zheng
Anna Kalinskaya will serve to get this deciding set under way.
Let's go.
Kalinskaya 7-6 (7-4) 3-6 Zheng
Both players have nipped for a bathroom break before the third set.
Which one is this way going?
Kalinskaya 7-6 (7-4) 3-6 Zheng
Chanda Rubin
American former world number six on BBC Radio 5 Sports Extra and BBC Sounds
Maybe that sense of urgency - the fact that she had to win this set to stay in the match - helped Zheng that bit more.
*Kalinskaya 7-6 (7-4) 3-6 0-0 Zheng
Zheng makes the perfect start as she aims to serve out the set but a double fault stops her progress.
She responds with a couple of winners before hammering a final ace down the middle to force a decider!
Kalinskaya 7-6 (7-4) 3-5 Zheng*
Zheng goes on the attack and may just get her reward her.
The 12th seed has a first break point of the set at 30-40 after Kalinskaya misses a backhand...
Gets it! Zheng is able to take full advantage as Kalinskaya suffers a dip, the Russian conceding the break with a couple of misses.
Now, a chance to serve for the set.
*Kalinskaya 7-6 (7-4) 3-4 Zheng
Having lost the first-set tie-break, every game is crucial now for Zheng Qinwen.
The 12th seed does what she must on serve, guiding a backhand cross-court for a 4-3 lead.
Kalinskaya 7-6 (7-4) 3-3 Zheng*
The occasion, despite how unfamiliar it is to the world number 75, does not appear to be getting to Anna Kalinskaya at all.
The Russian continues to look cool and calm as the second set unfolds, swiftly settling a hold to love.
*Kalinskaya 7-6 (7-4) 2-3 Zheng
A very timely ace. Zheng gathers herself following that series of misses to hold serve. Still very little to separate these two!