Hello and welcome to LIVE updates of the ATP World Tour finals clash between Stan Wawrinka and Marin Cilic at the O2 Arena. Both of these players lost their opening matches in straight sets so it's pretty much a win or bust scenario in their respective bids to make the semi finals. The players are due on court at 8pm GMT.

Who impressed you most in the mannequin challenge; Marin or Stan?

Worth pointing out Cilic and Wawrinka have met here at the O2 in the past too. Wawrinka edged it 6-3 4-6 6-3 at this stage in the 2014 event.

Tonight's doubles action is heading into a match tie break. That means there will be a slight delay in Wawrinka and Cilic taking to the court.

Injured rib the issue with Monfils. Claims it's got worse and prevented him from practicing today.

BREAKING NEWS: Monfils has withdrawn from his final match through injury. That means Djokovic will meet David Goffin tomorrow in the final round-robin matches in Ivan Lendl group. Goffin has been on standby all week and at least gets an opportunity to sample a bit of the action.

Cilic gave a good account of himself in his opening match against Murray, despite going down in straight sets. The Croatian had some big chances and will come into this against the maverick, Stanimal hopeful of producing a shock. Of course, the most memorable feature of his encounter with Murray were those rather colourful shorts!

PREVIOUS IN 2016: The two players have met once this year in the final in Geneva. Wawrinka won 6-4 7-6 to lift the trophy.

HEAD-TO-HEAD: Wawrinka owns the head-to-head with a 10-2 record. The Swiss has won the last six with Cilic's two successes coming back in 2010.

Wawrinka is aiming to edge past Milos Raonic and keep Kei Nishikori at bay in a three-way tussle to be the end-of-year no.3. It would be the first time for the Swiss and cap another year in which he won a major, having lifted the US Open in September. Cilic is currently at a career high of seventh in the world.

Earlier, Andy Murray defeated Kei Nishikori in a dramatic three-set encounter to seize control of this pool. The world number one will qualify for the last four if Cilic triumphs tonight.