Cash, working for BBC's Radio 5 Live, called the lengthy break "legal cheating", lashing the 18-time grand slam winner for his approach. Roger Federer receives treatment during the Australian Open final against Rafa Nadal. Credit:AP "It's cheating and it's being allowed. It's legal cheating but it's still not right," he said. It was a rare move by Federer who has prided himself on not abusing the rule that allows players to leave the court and receive medical assistance. He also underwent off-court treatment during his semi-final win over countryman Stan Wawrinka.

Quizzed about his decision to seek treatment after Nadal had regained the momentum by forcing the match into a deciding set, Federer said he was completely comfortable with his tactics. Roger Federer en route to victory. Credit:Getty Images "Look, I mean, I explained myself a couple of days ago after the Stan (Wawrinka) match," Federer said. "After he (Wawrinka) took a medical time-out, I thought I could also take one for a change and see if actually something like a massage during the match is actually going to help me. It did a little bit potentially. I'm not sure. "And then today after probably – well, I felt my quad midway through the second set already, and the groin started to hurt midway through the third set.

"I just told myself, 'the rules are there (so) you can use them'. I also think we shouldn't be using these rules or abusing the system. I think I've led the way for 20 years. "So I think to be critical there is exaggerating. I'm the last guy to call a medical time-out." Nadal was asked about Federer's move but the Spaniard didn't want to criticise his rival. "No opinion about that. I don't know what's going on," Nadal said. Federer also had to deal with the unusual circumstances of winning his fifth Australian Open after Nadal made an unsuccessful challenge against a line-call on Federer's second match point.

The Swiss was extremely confident his forehand winner had clipped the line, but he had to delay his celebrations as Nadal turned to Hawkeye. "I guess I've been there before at some point. I can't tell you which finals or – not a finals maybe, but some matches end this way. So we've seen it before," Federer said. "Of course, it's slightly awkward to win this way. Nevertheless, emotions poured out of me. I was incredibly happy, as you can imagine. Then, of course, I was also seeing my entire support team, (wife) Mirka, everybody else going bananas. It was cool. Loading "I knew from that point on, like, I actually did really win. That was a great feeling."

- with AAP