'What's going on?' Maths mayhem at ATP World Finals

LONDON: Anyone know what's going on?" asked Andy Murray. He didn't know, Roger Federer didn't know, and Juan Martin del Potro thought he did know - but he was wrong.

That was the nailbiting situation at London's O2 Arena as three of the planet's top tennis players were left clueless as to whether they had made it through to the semifinals of the season-ending ATP World Tour Finals.

Two of them had qualified from Group A - Del Potro and Federer, as it turned out - with Murray edged out of the $5-million tournament by the tightest of margins on an ATP statistics boffin's calculator.