Geoff MacDonald of the New York Times wrote an excellent article about how Roger's anger gave him the energy boost to win the fourth set versus Murray, but in the end may have cost him the match.
The incident as MacDonald recalls it:
At 6-5 in the fourth set, with Andy Murray serving for the match and a spot in the Australian Open final, Roger Federer hit a ball close to the baseline that Murray thought was out. No call was made, and Murray pantomimed displeasure — just for a moment — then played on.
When Federer hit an approach shot and attacked the net, Murray laced a down-the-line forehand passing shot that fooled Federer. What happened next was straight out of the animal kingdom, as Federer glared, gestured aggressively, then yelled at Murray. Murray’s response was to curl his lips upward in a sneer, and for 10 seconds or so the two men looked more like bonobos or gorillas tangling territorially over a prospective mate than two of the best tennis players in the world fighting for a spot in a Grand Slam final.
For Federer Anger Goes Only So Far, NY Times
MacDonald explains that "anger, like rocket fuel, burns fast and furious". So, Federer used the adrenaline rush he gained from the incident with Murray, but the boost in energy also depleted his emotional energy tank leaving him with not enough to compete against a fitter, stronger Andy Murray.
I have been talking to players about this concept for some time. If you allow your emotional energy to peak so high either in a positive or negative manner it can give you a boost, but what if you have another hour of tennis left? Can you maintain the energy needed and avoid a letdown when the adrenaline rush ends? Probably not.
I believe in using your emotions to your performance advantage. We have evolved as human beings with these emotional instincts for a reason - to help us survive and thrive. As tennis players we need to use these emotions to our advantage. Use anger to give us a boost in energy, frustration to remind us to stick to the game plan, happiness to find the joy in tennis and motivate our efforts... So, a fist pump here, a come on growl there, it is good if that fits you.
However, we must display our emotions in moderation; find the even keel if that makes sense. When our emotions erupt it is hard even for the most emotionally tough tennis players in the world to keep the emotional intensity at the level it needs to be.
Think of displaying your emotions as a controlled burn. Use your emotions in a positive manner (even negative ones) but not with exaggerated displays. Save the huge emotional outburst for winning the last point. Then it won't matter if you exhaust everything in the tank.
Read these other Emotional Toughness posts:
Stosur wins US Open 2012
Learning Mindset of Djokovic and Nadal
Harrision Loss Due to Control not Skill