After the most up-and-down season in Andy Murray's career, it is perhaps not surprising he is playing down his chances of beating a player he has not lost a set to since January.
The fact his opponent in his second round-robin match at the Barclays ATP World Tour Finals in London tomorrow is Roger Federer also explains the British number one's caution.
The pair's rivalry stretches back five years to Murray's first appearance in an ATP Tour final in Bangkok. The Scot can boast an 8-5 winning record over that time but the bigger the occasion, the more Federer rises to it.
Murray's two grand slam finals, in America in 2008 and Australia this year, have been chastening experiences while their meeting at the same stage of last year's tournament at London's O2 Arena also went the way of the Swiss.
Recent results have been more encouraging, though, with Murray claiming straight-sets wins over Federer in Masters Series finals in Toronto and Shanghai during the last three months.
The 23-year-old said: “Every time you play against him it's tough. It's obviously good to win against him. But in tennis every match is completely different. It's a new day. I played great on Sunday, I could play horrible on Tuesday.”
Murray could not have had a better start to his campaign at the end-of-season eight-man event on Sunday as he raced to a 6-2 6-4 victory over Robin Soderling, who was the form player going into the tournament and last week overtook Murray to become the new world number four.
The crushing nature of Murray's win, coupled with Federer's 6-1 6-4 victory over David Ferrer in Sunday’s other Group B clash, have already made the pair hot favourites to reach the last four.
Murray added: “The most important thing is to win the matches. I need to try and win the next match.
“Last year I was unlucky. It came down to one game or something. I'd be surprised if that happens again or if it's ever that close again.”