If Andy Murray is looking for chinks in the armour of the world's greatest player going into today's Australian Open final then he could do worse than take a look back at something Roger Federer said in the aftermath of his five-set defeat by Juan Martin del Potro in last year's US Open final.
Federer had strangely faded away in the final set as the Argentinian claimed his first slam title. "He hung in there and did well. In the end, he was just too tough. Just the way it is," Federer said.
On the face of it, that seems fair enough. Del Potro played a great match and deserved his first major triumph. But it was the way the match slipped away from Federer in the final set that was intriguing. The Swiss is justly proud of how he has kept himself in great shape throughout his career, something that has, without doubt, been a massive factor in his sustained success. You cannot win a grand slam title these days without being a top athlete. But as he was against Nadal in Australia, he seemed spent in the final set.
With the temperature due to be well past 30C (86F) when the match begins this morning, fitness and conditioning may well become an even bigger issue. Federer makes a lot out of the fact that he does his off-season work in the intense heat of Dubai, while Murray's programme in Miami is well-documented and, having transformed himself into a top-class athlete, the Scot is arguably the fittest player on the tour.
Should the final go to five sets, he may feel he has the edge. In the heat, the ball flies a little faster, which could make it even more interesting because Murray loves it when the courts quicken up, as shown by the fact that eight of his 14 tour titles have come indoors.
All that could be irrelevant if Federer comes out and destroys Murray, as he did in the 2008 US Open final. That, though, was Murray's first grand slam final and a combination of understandable nerves and fatigue after playing his semi-final over the previous two days because of rain -- while Federer had the day off -- were strong contributing factors.
Even then, Murray still had a chance -- he would have gone ahead by a break in the second set but for an atrocious line-call -- and though he never claimed he would have won the match had that gone his way, Federer was beginning to look tight. You just never know.
The Swiss deservedly goes into the match as favourite, not least because his records are incredible. This is his 18th grand slam final in the past 19 events and his 22nd overall. It is his seventh straight Australian Open final and this tournament marked the 23rd consecutive time he has reached the last four of a slam.
They are records that would strike fear into any opponent, but 16 months on and Murray is an altogether different animal and he is not frightened of Federer.
That is in no small part because he has won six of their 10 meetings. Federer has won the past two but there is no question that Murray gets inside the head of the Swiss, something that was further in evidence when he began the psychological warfare after his semi-final win over Jo-Wilfried Tsonga.
The pressure is on Murray, Federer claimed, while also suggesting that having failed to win his first slam final, it might be more difficult for him to win one at the second attempt.
This is nothing new from Federer. Throughout his career, he has continually come out with statements that from the mouths of any other player -- particularly an American -- would have been dismissed as arrogant and disrespectful. As one television commentator said: "He's the most elegant trash-talker in sports."
Murray's success against Federer has been built on his solidity, variety and his ability to make his opponents play in a style with which they are not comfortable. Federer has often said that when he plays Murray he feels the match is on his racquet; if he plays well, he'll win; if he plays badly, he'll lose. But as he claimed after beating Tsonga: "When was the last time I played a bad match? I don't know. A long time ago, I think."
He is not exactly running scared but Federer is clearly concerned. Why else would he claim that Murray has not really improved from when they played in the final in New York? In the 16 months since that match, Murray has won eight of his 14 ATP Tour titles and become one of the most consistent players in the world.
In their past two matches, Federer has come out firing, trying to overpower and bully the Scot. But Murray usually plays well against the Swiss, partly because he loves taking on the world's best. His natural style works well: his short slices bring Federer to the net even when he does not want to come in and his passing shots are second to none. If the match becomes a war of attrition, conducted largely from the baseline, it will play into Murray's hands and it would be no surprise to see him pepper the Federer backhand.
"Without taking anything away from him, a few times he played me I wasn't at my very, very best," Federer said, immediately taking some of the credit away from Murray. "In Dubai [in March 2008] the first time we played, I had just come back from resting after my mono [glandular fever]. I know some don't like to hear it. Some still don't believe me for some reason. We had some close matches on many occasions where I thought I was in control and I ended up giving the match away by making errors of my own.
"That was definitely because of his play and the way he plays. So I think the head-to-head could be quite different. But that's why I don't really care too much about that. Best of five sets is very different."
Best of five sets is very different, as Del Potro and Nadal showed last year. While Federer suggests Murray will need to win the first set to settle his nerves, Murray has the advantage of knowing that fitness should not be an issue. Mentally that could make all the difference.
Murray v Federer,
BBC2, Eurosport, 8.0am