Andy Murray will bid for victory against Fernando Verdasco this afternoon hoping it will be enough to send him through to the semi-finals of the Barclays ATP World Tour Finals.
The British number one's three-set defeat by Roger Federer at London's O2 Arena on Tuesday threw Group A wide open, with all four players still in contention for the two semi-final spots.
A straight-sets victory would put Murray through while a straight-sets defeat would see him eliminated, but any other result would leave him waiting on the outcome of the night match between Federer and Juan Martin del Potro.
After Rafael Nadal's shock exit last night following defeat by Nikolay Davydenko, the tournament organisers will desperately hope the home favourite makes it through.
Murray said: "The only important thing is to try and qualify from the group, whether you win one match, three matches, two matches.
"Last year I won three, lost in the semis. This year I could potentially lose two matches and win the tournament. So you just never know.
"The match against Verdasco, obviously I'll try and win. If I do that, there's a good chance I go through."
Nadal's fate was sealed with a 6-1 7-6 (7/4) defeat by Nikolay Davydenko last night, which followed on from his 6-4 6-4 loss to Robin Soderling on Monday.
The world number two, though, saw positive signs in his second-set fightback and is optimistic 2010 will see him rediscover his best form.
"I think mentally I was better," he said. "That's the important thing, that I improved a little bit. Every day I'm trying a little bit more. I am ready to practise hard. I have motivation to play another time my best tennis.
"I think without playing very good tennis in all the matches, I had my chances against the best players of the world," he added.
Davydenko, who lost to Novak Djokovic in last year's final, is playing at the end-of-season tournament for the fifth successive year but he remains much less high profile than many of his rivals - and that is just the way he likes it.
"Today it was Nadal, Nadal, Nadal," he said. "It's good. That way I have no pressure and I can play my tennis. I show my best tennis and I win. If nobody is waiting (for me to win), maybe it's good for me and easier to win the tournament."
The earlier match in Group B saw Soderling become the first player to qualify for the last four thanks to a 7-6 (7/5) 6-1 victory over Djokovic.
The Swede, who only qualified for the event as a reserve after Andy Roddick withdrew injured, said: "It's great. I won two matches in straight sets against the world number two and number three. I couldn't have asked for anything more."
A downbeat Djokovic, who went into the contest on an 11-match winning streak but admitting he is running on empty, gave credit to Soderling and believes the Swede is showing the best form out of the eight players.
"He has nothing to lose," said the Serb. "It's his first (World Tour Finals). He won four straight sets and absolutely deserved to qualify for the semi-finals. I think he's the best player so far in the tournament."