Federer is closing in on a return to the world No 1 spot after securing a 20th Grand Slam title in stunning fashion.

He overcame Marin Cilic in five dramatic sets at the Rod Laver Arena.

Federer won 6-2, 6-7, 6-3, 3-6, 6-1 in three hours.

And former Wimbledon champion Cash opened up his transformation.

“A few years ago you thought he was over the hill,” he said on BBC radio. 

“But he redesigned his game, he's fit again and he's come back a better player. He's changed his racquet and his backhand.

“I don't know if he'll play the French Open but I don't see anyone touching him at Wimbledon.

“On a fast court, Federer is my favourite every time.”

Federer was emotional after victory and sparked fears he may retire from the sport after failing to say ‘see you next year’ to the Australian crowd.

And Greg Rusedski has told tennis fans to enjoy him while they can.

“What he has accomplished is sensational, 20 major titles and it doesn’t look like there is anything stopping him,” Rusedski said on Eurosport.

“So enjoy the time Roger Federer is playing tennis. 

“He’s not only one of the greatest tennis players, one of the greatest athletes of our generation. 

“You feel sorry for Marin coming in second place but as we all said, he made it a great match. 

“But the great man himself was just too good on the day. 

“I love to see that emotion, it still means so much to him after all this time. 

“He’s just as excited having won his twentieth as he was to have won his first.”