Top competitors are able to 'bring their best' at the end of a contest because they've learned more and more through the contest about the opponent, environment and conditions and are able to put that knowledge into practice at critical moments in the closing stages.
No better example of this than Lewis Hamilton yesterday at the Portuguese Grand Prix in which he broke Michael Schumacher's all-time Formula 1 win record.
Hamilton said, 'It is no secret that today was about tyre temperatures, I felt through the race that I was learning lap on lap more about the circuit. I was trying lots of different lines and discovering new lines that worked well. The wind direction was very tricky, lots of head winds and cross winds and tail winds. There are some you can use in your favour and others get in the way. The key is minimising the loss through the tail winds.'
Clearly a master-tactician and competitor at the height of his powers.