Hello and welcome to live updates of the Nitto ATP World Tour finals round-robin clash between Dominic Thiem and Pablo Carreno Busta. The latter replaces the injured world No.1 Rafael Nadal in Pete Sampras group and can still qualify if he wins the next two matches.

GAME, SET AND MATCH! - CARRENO BUSTA 3-6 6-3 4-6 THIEM. Dominic Thiem hits back from 15-30 to serve it out and battle past the injured Rafael Nadal's replacement to set up a winner-takes-all clash with David Goffin on Friday. Grigor Dimitrov is already qualified, so PCB's hopes are over. It turned into a pulsating battle lasting two hours and six minutes, but despite the Spaniard's dogged defence it was the Austrian world No.4 who just had too much in his armour in the end.

BREAK! - CARRENO BUSTA 3-6 6-3 4-5 THIEM. PCB's resistance is broken - and this time it may be a bridge too far to recover. Thiem continues to hit big and gets what he will feel is a deserved reward for how much he has knocked on the door throughout the contest. The Austrian will now serve for the match.

CARRENO BUSTA 3-6 6-3 4-4 THIEM. Cracking reply from Thiem. An 11th ace, a rasping forehand and a bullet first serve help him through a rapid love hold.

CARRENO BUSTA 3-6 6-3 4-3 THIEM. Nadal may not be here anymore, but we've still got a Spaniard showing all those fighting qualities the world No.1 is famed for. A sizzling pass down the line proves too hot to handle and tees up double break point for Thiem. PCB hits back to save both and then a third from deuce with a sensational winner down the line. The world No.10 produces a lovely serve and volley combo to finish. Thiem will wonder what he's got to do. He's had so many chances, but it's his opponent with the edge at a crucial point in the match.

BREAK! - CARRENO BUSTA 3-6 6-3 3-3 THIEM. This has developed into a really intense battle. Thiem keeps throwing the kitchen sink at PCB, who has started to return it with interest. The Spaniard fights back to deuce and somehow pulls off the break to level. Thiem will be hugely frustrated. He was his own worst enemy there.

CARRENO BUSTA 3-6 6-3 2-3 THIEM. Carreno Busta stays in touch - just! The Spaniard blows a 40-0 lead and faces break point as a beast of a crosscourt forehand from Thiem leaves his defences breached. The Austrian can't convert as he fizzes a return long before PCB wriggles out of danger with a wide ace.

CARRENO BUSTA 3-6 6-3 1-3 THIEM. PCB has got a good read on the Thiem second serve. Fortunately for the Austrian his first serve is still proving effective and he maintains his lead when the world No.10 lashes a forehand attempt long.

CARRENO BUSTA 3-6 6-3 1-2 THIEM. Carreno Busta gets himself on the board with a much-needed simple hold.

CARRENO BUSTA 3-6 6-3 0-2 THIEM. Dom consolidates courtesy of some neat play at the net and a bruising forehand Pablo can't get back. A rollercoaster ride for the Spaniard so far. Can he hit another high to drag himself back into it?

BREAK! - CARRENO BUSTA 3-6 6-3 0-1 THIEM. That's a fabulous response from Thiem. The errors were mounting up and frustrating him in Set 2, but he seems to have drawn a line under it. He comes out all guns blazing and finds a way through PCB's defence to break to 15.

SET! - CARRENO BUSTA 3-6 6-3 THIEM. He's level! PCB breaks to take us into a decider. The Spaniard earns himself a set point with a sublime return winner and Thiem bottles it, slapping a tight backhand into the net.

CARRENO BUSTA 3-6 5-3 THIEM. Carreno Busta has managed to neutralise some of the missiles being fired at him. The longer the rally, the more likely he is to tease out an error from Thiem. He holds firm again to move within a game of taking this to a decider.

CARRENO BUSTA 3-6 4-3 THIEM. Carreno Busta shows wonderful reflexes with a delightful volley at the net, but Thiem powers back to stay in touch at the business end of the set.

CARRENO BUSTA 3-6 4-2 THIEM. A topsy-turvy game goes the way of the Spaniard after Thiem had turned up the heat at 15-30 and deuce.

CARRENO BUSTA 3-6 3-2 THIEM. This time it's Thiem's turn to mount the recovery as he hits back from 0-30 to reel off the points with some hefty first serves. He's still very much in this set, but PCB has definitely moved up a gear to make it far more competitive.

CARRENO BUSTA 3-6 3-1 THIEM. After a very sloppy finish to the last game, Thiem looks to make immediate amends. The Austrian earns double break point, but fails to convert as he sizzles a backhand inches wide down the line. The man Brad Gilbert dubbed 'Busta Move' takes full advantage of the reprieve, frustrating his opponent by prolonging the rallies with great defence to consolidate the hard way.

BREAK! - CARRENO BUSTA 3-6 2-1 THIEM. Well, where did that come from? Thiem races 40-0 up - but then implodes! The Austrian drags wide of the tramlines on PCB's first break point of the contest as the Spaniard roared back to take five in a row. Match on?