Gael Monfils takes on Dominic Thiem at the ATP World Tour Finals

Gael Monfils takes on Dominic Thiem with both men having suffered defeat in their first group games at The O2

ATP World Tour Finals debutants Gael Monfils and Dominic Thiem meet on Tuesday knowing a victory is crucial to their hopes of progressing at The O2.

The pair suffered defeats on the opening Sunday of the event, Thiem slipping to a three-set defeat against former world No 1 Novak Djokovic having claimed the opening set, while Monfils gave big-serving Milos Raonic little to worry about in a 6-3 6-4 defeat.

With just one more game to play, both players know a win is all-important particularly with Djokovic the dominant force in the group, the Serb's win over Thiem means he has won all 24 matches played against his rivals in the Lendl group.

Thiem will be the happier with his opening display having claimed a first set tie-break against Djokovic and with his final match against a Raonic who has struggled with injury, he will feel he is still in with a chance of making the last four on his first appearance at the season-end event.

Monfils could not muster anything against Raonic's powerful serve and knows the match against Thiem may be his best chance of keeping his hopes alive with Djokovic still to come.

The Frenchman is up to a career high No 6 in the world rankings, while Thiem has claimed four titles this year, only Djokovic and world No 1 Andy Murray have claimed more.

Thiem won the opening set against Djokovic before suffering defeat

Both __can claim to be enjoying their most consistent year on tour and their only 2016 meeting saw Thiem awarded the victory when Monfils was forced to withdraw from their last 16 encounter in Cincinnati.

Their only other career meeting saw Thiem emerge victorious from a three-set battle on clay in 2015 but the conditions at The O2 are likely to level up an even-looking contest.

Opening up Tuesday's action in London will be the doubles match between Jamie Murray and Bruno Soares who face Bob and Mike Bryan in the Edberg/Jarryd group.

Both pairs kicked off their campaigns with straight sets victories on Sunday and another win should assure them of a place in the last four.

Second seeds Murray and Soares are looking to regain the No 1 ranking while the Bryan brothers are chasing a fifth success in the season-end championship having last claimed the title in 2014.

All the action from the World Tour Finals between November 13-20 will be live on Sky Sports across the week and if you are out and about you __can follow on our Sky Sports apps and the website via our live blogs. Full schedule here.