Hello and welcome to LIVE updates of the women's singles quarter final between the USA's Sloane Stephens and Latvian 16th seed, Anastasija Sevastova. The winner will meet Petra Kvitova or Venus Williams in the semi finals.

GAME, SET AND MATCH! - STEPHENS 6-3 3-6 7-6 SEVASTOVA. Stephens has done it! The American's comeback from injury continues to gather pace as she books her spot in her second ever Grand Slam semi final with a 7-4 triumph in the tie-break decider. A sizzling backhand winner down the line is a fitting way to conclude a massive battle with the Latvian No.16 seed that lasted a lung-bursting two hours and 27 minutes. She will now meet Petra Kvitova or Venus Williams in the last four.

TIE BREAK UPDATE: A miscue into the tramlines from Nastja and an error off her backhand after a lengthy rally put Stephens back in control at 5-3. The American fails to punish a weak second serve but then snares three match points when the Latvian makes another unforced error. Can she see it out from here?

TIE BREAK UPDATE: It's 3-3 at the change of ends. A scorching crosscourt winner from Stephens is the pick of the points, but she leaks two unforced errors to allow Sevastova back in from 3-1 down.

TIE BREAK TIME - STEPHENS 6-3 3-6 6-6 SEVASTOVA. Quite superb from Sevastova. She holds to love again and we will head into a tie-break to decide who makes the last four of the 2017 US Open.

STEPHENS 6-3 3-6 6-5 SEVASTOVA. Jittery stuff on the first point, but Stephens rattles through the next four to guarantee herself the minimum of a tie break to decide this match. Same drill again for the No.16 seed. Any slip now will see her crash out of the competition.

STEPHENS 6-3 3-6 5-5 SEVASTOVA. Stephens doesn't do enough as Sevastova helps herself to an emphatic hold to love. A corking forehand winner and a sliced dropshot that leaves Sloane stranded are the pick of the points. That's how you handle pressure.

STEPHENS 6-3 3-6 5-4 SEVASTOVA. The crowd around Arthur Ashe stadium erupt! Stephens digs out a hold from deuce, forcing an error from her opponent with a fizzing crosscourt forehand. She has the scoreboard advantage at the business end of the match. Huge moment for Nastja now, who must hold to stay in the tournament. No pressure...

BREAK! - STEPHENS 6-3 3-6 4-4 SEVASTOVA. The tension on serve is clear to see. Stephens fights back once more, breaking on the second chance on double BP with a pick up from a dropshot that just caught the baseline. She's still alive in this deciding set, but could really use a routine service game right now. Sevastova is unlikely to oblige...

BREAK! - STEPHENS 6-3 3-6 3-4 SEVASTOVA. The buoyant mood inside Ashe evaporates. Stephens battles hard and looks in the ascendancy at 30-30 at the end of a gruelling rally, but then slaps a tired crosscourt forehand into the net. She follows up with an ill-advised forehand wide of the right tramlines she is facing and gives the momentum right back to Sevastova.

BREAK! - STEPHENS 6-3 3-6 3-3 SEVASTOVA. And that's why it's worth fighting to the death. Sevastova was a point away from the double break in the last game - but now it's all square! Stephens comes out re-energised, snaring triple break point and making it count by outlasting the Latvian in a bruising rally on the second of them. Who's your money on now?

STEPHENS 6-3 3-6 2-3 SEVASTOVA. A scream of delight or was that a full-on roar? Stephens isn't done yet. She looked to be after surrendering a 30-0 lead to face BP courtesy of poor shot selection and stress-related errors. But the crowd stay with her and she battles hard, producing back-to-back blistering winners off either flank to stay in touch.

Sloaney wishes her opponent was too...

STEPHENS 6-3 3-6 1-3 SEVASTOVA. All of the momentum is with Nastja. She consolidates for the loss of one point and can see that semi final spot growing larger on her horizon. Stephens looks forlorn. She has a chance to battle back but wildly misses an overhead by some distance.

BREAK! - STEPHENS 6-3 3-6 1-2 SEVASTOVA. The No.16 seed strikes an important blow! The crowd try to lift Stephens as she wilts under the pressure to trail 15-40. She staves off one BP but can do little to deny the Latvian when she pummels an outrageous crosscourt forehand winner way beyond the American's reach.

STEPHENS 6-3 3-6 1-1 SEVASTOVA. Nastja responds with a solid game to 15. Neither player dare to blink here.

STEPHENS 6-3 3-6 1-0 SEVASTOVA. A real psychological boost for Stephens as she survives an edgy opening game to lead from the off in Set 3.