Venus Williams beats Carla Suarez Navarro 6-3 3-6 6-1 in last 16
Two-time US Open champion through to quarter-finals
Maria Sharapova loses 5-7 6-4 6-2 to Latvia's Anastasija Sevastova
Garbine Muguruza v Petra Kvitova - 01:00 BST start approx
Anastasija Sevastova is crouched down at the bottom of the court, waiting for her opponent to come back from her comfort break - which is actually a change of outfit. It's a long break.
It feels a bit unnecessary, but it's within the rules.
Jill Craybas
Former world number 39 on BBC Radio 5 live sports extra
I think Sevastova did a good job of staying in a lot of points by defending well and anticipating well.
Sharapova helped her by dropping her first serve percentage which meant Sevastova could get the break.
Russell Fuller
BBC tennis correspondent at Flushing Meadows
This match has the deciding set it deserves. Sevastova has not been at all phased or psyched out by Maria Sharapova, who has played some very high quality tennis at times. You have to admire her grit.
Sevastova 5-7 6-4 Sharapova*
The crowd groan along with Sharapova as a couple of silly errors hand Sevastova a 30-0 lead.
'C'mon,' yells the Russian as she executes a big return to get off the mark.
And then Sevastova shanks outside the whitewash for 30-30. This is nail-biting stuff!
The Latvian pulls out a huge serve to bring up set point and then Sharapova's return goes long! We are going to a decider.
Mats Wilander
Former world number one on BBC Radio 5 live sports extra
When Sharapova gets her first serve in play she is almost unplayable, it is such a weapon.
She needs to find a way to keep her first serve percentage above 60 per cent.
*Sevastova 5-7 5-4 Sharapova
Maria Sharapova needs to hold to stay in this set.
So she decides to do it to love. That'll do nicely.
Image source, Getty Images
Gigi Salmon
BBC Radio 5 live sports extra commentator at Flushing Meadows
What a great hold from Sevastova. She has such good hands and moved forward very quickly. It makes it tougher for Sharapova to use the drop shot.
Sevastova 5-7 5-3 Sharapova*
Sharapova has a second break point but she hits out and it goes away. The Russian goes to challenge, but realises she's only got one remaining, so holds back.
Sevastova takes the advantage and holds after another net battle.
Meanwhile Britain's Jamie Murray and his men's doubles partner Bruno Soares are playing their second-round match over on court 17.
The defending champions and fourth seeds are locked at 4-4 in the first set against New Zealand;'s Marcus Daniell and Brazil's Marcelo Demoliner.
Follow their progress with our live scores page.
Image source, Getty ImagesSevastova 5-7 4-3 Sharapova*
More screams of delight from Sharapova as she pushes her serving opponent to 30-30.
Make that 30-40, with a lofted forehand cross-court to earn a break point.
Sevastova nullifies the danger with a big serve which the Russian can only return into the net.
Same again for the next point, as Sevastova brings up the advantage. But the Latvian hits long..back to deuce.
Jill Craybas
Former world number 39 on BBC Radio 5 live sports extra
Unbelievable point there from both players but just incredible fight from Sharapova to win that rally.
Image source, Getty Images*Sevastova 5-7 4-3 Sharapova
Sharapova takes a deep breath to collect herself as she nets a backhand and she's even more irritated when, controlling a rally, she slaps a loopy forehand long for 15-30.
There's a shout of 'come on!' though as Sevastova works a forehand out, and an ace puts the Russian in front.
Then a stunning rally, Sevastova pushing Sharapova deep before the two scuffle at the net, and two stunning left-handed forehands turn the point Sharapova's way. She gets a near-standing ovation from her fans in the crowd.
Sevastova 5-7 4-2 Sharapova*
Sharapova goes after Sevastova's second serve but plonks a forehand long as she tries to get her footing back in this match.
She gets on the board though as Sevastova charges to meet a drop shot, gets to it, and slices her return into the net.
However, her 27th unforced error brings about a yell of frustration from the Russian, and Sevastova unfurls a drop shot to hold.
*Sevastova 5-7 3-2 Sharapova
Another exhaustive rally sees Maria Sharapova execute what she does best - an explosive forehand winner.
And it's Sevastova's turn to land some dodgy shots outside the lines, as Sharapova also holds to love.
Jill Craybas
Former world number 39 on BBC Radio 5 live sports extra
Sharapova is having to work a bit harder to finish points, Sevastova is making her hit one more shot. That is what is making unforced errors creep in.
Image source, ReutersSevastova 5-7 3-1 Sharapova*
A delightful touch at the net moves Anastasjia Sevastova 30-0 up.
The Latvian benefits from some sloppy play from Sharapova to hold to love.
Jill Craybas
Former world number 39 on BBC Radio 5 live sports extra
Great depth from Sevastova there in the last few points, forcing Sharapova into unforced errors.
*Sevastova 5-7 2-1 Sharapova
You know that emoji with the heart eyes? I'd use that right now to describe Sevastova's forehand winner just then. She took a second, waited for the right moment and belted into the perfect position to beat her opponent.
The Latvian is battling hard and earns break point after deuce, thanks in part to a clip of the net which outfoxed Sharapova.
Sevastova thinks she's got the break with a forehand on to the baseline. Sharapova challenges, but it's well in.
Image source, Getty ImagesJill Craybas
Former world number 39 on BBC Radio 5 live sports extra
Sevastova has to do more on that second serve. Take a little bit more risk and go harder.
Sevastova 5-7 1-1 Sharapova*
Sharapova's got another break point. She's meaning business right now.
Unfortunately for the Russian, she plants a return into the net so we go to deuce.
Sevastova takes the advantage when her opponent hits wide, and she holds with a tricky dropshot.
A big game for the Latvian.