Andy Murray has said that he must begin the ATP World Tour finals strongly to stand any chance of winning in London.
The end-of-season showpiece features only the world's top eight players for the year so every match will be a test for the Scot.
He takes on Spain's David Ferrer in his first match at around 2pm on Monday, with Roger Federer beginning proceedings against Jo-Wilfried Tsonga this afternoon.
"You have to be right on your game from the first match," said 24-year-old Murray.
"Sometimes you work your way into an event. Here you have to play your best, simple as that."
The format sees two groups of four players face off in a round-robin format, before the top two from each group advance to the semi-finals to fight for a place in next Sunday's final.
Murray has been placed in a group with world number one Novak Djokovic, Tomas Berdych and Ferrer.
