Hello and welcome to LIVE updates of the ATP finals Green Group clash between GB’s Cameron Norrie and Casper Ruud. Norrie comes in from the sidelines to make his finals debut as second alternative after Stefanos Tsitsipas withdrew from the tournament with a right elbow injury. The players are due on court from 20.00 GMT.

NORRIE 6-1 0-1 RUUD. Casper stops the rot with a much-needed hold to 15 to kick off Set 2. He needs to dramatically swing the momentum here. Norrie was well on top in the opener.

SET! - NORRIE 6-1 RUUD. That is some set of tennis from Norrie. He’s looked the more assured player throughout and deservedly notches up the opener for a breadstick, serving it out on his third set point from deuce after Ruud had threatened to pull a break back with a rasping backhand up the line. The Brit even won a battle of opinions on a double bounce pick-up at the net to earn a replay of a point on his way to coming through a tricky situation.

BREAK! - NORRIE 5-1 RUUD. It just gets better and better for Norrie. He’s helped a fair bit by Ruud who again blazes his forehand long to gift the Brit a double break. He will now serve for the first set.

NORRIE 4-1 RUUD. Clutch from Cam as he conjures up a huge first serve at 30-30 to take charge before consolidating his break with a crisp overhead.

BREAK! - NORRIE 3-1 RUUD. Lift off! Norrie’s deep returns prove key as Ruud’s forehand misfires at the wrong moments. The Norwegian looks to fend off the BP from deuce but sees a crosscourt attempt clip the net and fly wide.

NORRIE 2-1 RUUD. Cam turns to his box and gives them a familiar pump of the fist as a block volley loops deep into the open court to secure another steady service game.

Suits your sir!

NORRIE 1-1 RUUD. Casper responds with an equally efficient hold for the loss of one point.

NORRIE 1-0 RUUD. Norrie roars out of the traps and then avoids a potential fight back from 40-0 up as he challenges a Ruud ‘winner’ called in and gets the call right. Just the start he would have wanted; nice and solid.

Norrie has won the toss and opted to serve first. Cue the warm up!

DID YOU KNOW? Norrie becomes just the fourth Brit to play singles at the Nitto ATP Finals in its 52-year tournament history (also Andy Murray in 2008-12 and 2014-16; Henman in 1997-98 and 2004; Rusedski in 1997-98).

Earlier Novak Djokovic booked his spot in the semi finals with a ruthless straight sets win over Andrey Rublev. He will top green group - but who will join him in the last four? 

H2H: They have met once before with Ruud triumphing 6-0 6-2 two months ago in the San Diego Open final.