Roger Federer knows all about tie breakers turned heart breakers.

A fierce Federer fought off seven match points, including denying four match points in the tie breaker, to ignite a miraculous 6-3, 2-6, 2-6, 7-6(8), 6-3 AO comeback win over 100th-ranked Tennys Sandgren.

More: Federer's Match-Points Miracle

Federer's reward for a titantic comeback is an Australian Open semifinal clash vs. defending champion Novak Djokovic. The pair have combined to claim 13 of the last 16 Australian Open crowns.

Seven-time AO champion Djokovic dispensed a gut-wrenching defeat to Federer and Fed fans all over the world last July. 

A defiant Djokovic denied two championship points in the final set fighting off Federer, 7-6 (5), 1-6, 7-6 (4), 4-6, 13-12 (3) to successfully defend his Wimbledon title in The Championships' longest final—and first men’s major final decided in a fifth-set tie breaker.

Djokovic is 26-23 lifetime vs. Federer and knows major margins can be miniscule when they face off.

"Wimbledon last year, he had two match points, he was one shot away from winning that match," Djokovic said after sweeping Milos Raonic in the quarterfinals. "It's not like I've been dominating the matchups. I've had success against him, as you said, in Grand Slams in particular.

"But Roger is Roger. You know that he's always going to play on such a high level, regardless of the surface. He loves to play these kind of matches, big rivalries, semis, finals of Grand Slams."

The 20-time Grand Slam king, who took a medical timeout for treatment of a groin issue vs. Sandgren, said he believes he should be physically fine for his rematch with personal nemesis Djokovic.

"I don't know if you can call it an injury," Federer said of his groin issue. "It's just pain and problems. I need to figure it out now. But as it's not like in 18 hours, like you got a third round to play, semifinals, you have an extra day, adrenaline, there's a lot of things.

"Two good nights of sleep, doctors, physios. Hopefully we'll find out that it's actually nothing bad."

The 38-year-old Swiss has not defeated Djokovic in a Grand Slam match since scoring a four-set win in the 2012 Wimbledon semifinals.

Djokovic aims to impose his advantage on the Grand Slam court he's come to regard as his own turf.



"What he did today was really amazing. I mean, to come back and save seven match points at his age," Djokovic said. "I mean, he's still playing such a great tennis and proving that he deserves to be up there. He's a great fighter. Obviously I have lots of respect for him. But I've been feeling well on the court.

"I think if I continue playing the way I was throughout the tournament here and also ATP Cup, I've been building I think as the time passes by, in every match, I have more confidence, I feel better. In the end of the day, this is my favorite court, I mean, the court where I had the most success in my career. Hopefully things can come together for me in a positive way on Thursday and I can have a chance to win."

Photo credit: Mark Peterson/Corleve