The last time Roger Federer lost to Rafael Nadal was in the semi-final of the 2014 Australian Open. The scoreline read 7-6, 6-3, 6-3. The rivalry, in the eyes of many, was dead.

It is an important date because prior to that Federer had lost six consecutive matches to the Spaniard (the loss at the Australian Open was his seventh in a row) and after that he has lost none (winning five in a row for the first time).

As a result of all those losses, Federer knew that he needed to change something. His game – as it stood – was the perfect match for Nadal. The one-handed backhand couldn’t keep up with Nadal’s top-spin forehands and the slice posed no problems to the Spaniard. It was a huge gaping hole in the armour. One that the Swiss maestro was consciously aware of – to such an extent that his game started to breakdown because of it.

The more obvious answers to the problem at that point were physical. He needed to get stronger and faster because Nadal didn’t ever let up (he still doesn’t) and if you wanted to compete with him, you would have to do the same.

But there was also another – slightly more technical way of looking at it: switch racquets. The power and control generated from a racquet can be the difference maker at the highest level. But it can also throw off one’s game – if you are unable to control the power, your accuracy will fall and without accuracy, you are as good as a dead duck when playing against the top pros.

Still, Federer decided to take the leap of faith because frankly he was left with no option. In many ways, Nadal forced him into it; forced him to evolve; forced him to become the player he is today.

Just after his straight-sets demolition of Nadal at Shanghai, the Swiss champion once again mentioned his secret weapon.

“I think the bigger racquet head size allows me to come through the ball easier. I’m not having to slice the ball as much as I used to against him.

“It also helps me on the serve to be honest. My serve has been very consistent ever since changing the racquet and getting used to it.”

For a more detailed explanation of why Federer decided to change the racquet in the first place, we have to go back to 2014 – the year when he began trialling his new racquet. For 12 years before that (since 2002), he had been using a racquet head that was 90 square inches. Now, he settled for 97 square inches.

“For me switching racquets was not only about a larger head,” Federer had said in fall 2014. “I was also looking for a racquet that was more forgiving and could provide me with easy power. It was also important that my racquet was responsive and offered the same great feel I had grown accustomed to in my previous Wilson Pro Staff rackets. The larger racquet suits my attacking style, allowing me to play more aggressively and with less risk.”

The end result for Federer’s signature Pro Staff was one that featured the braided graphite and Kevlar just as his old racket had, but with a larger head for a “larger sweet spot”.

But just what is the sweet spot?

According to experts, sweet zones are areas on the stringbed where the power potential exceeds a designated amount. They are always longer than they are wide, because off-center hits twist the racquet and result in losing power.

But perhaps the one that mattered the most to Federer was that sweet zones are also comfort zones. The larger and “sweeter” the area of the zone, the less the racquet is twisting, rotating and recoiling. In a sense, perfect for the one-handed top-spin backhand that he needed to activate to get back in the game.

Players change/upgrade racquets all the time. And in that sense, Federer didn’t do anything unique. Even Nadal has changed his racquet recently. But usually it means a bump up in power... the playing style remains the same. But because Federer has added one more consistent ingredient to his game, the whole mix has changed.

He doesn’t need to keep running around his backhand and as a result even his court coverage and the angles are better/different. It took Federer some time to get used to the racquet and perhaps it will take his opponents longer to get used to him too.

As a 44-4 record in 2017 (six titles) shows, this Federer is like a whole new challenge now. One that is making his opponents sweat. One that his fans are loving. One that Nadal is possibly hating.

As someone once said, “the secret of change is to focus all of your energy not on fighting the old but on building the new.”

Given how Federer is doing... it sure seems like the right approach.