Roger Federer vs. Kei Nishikori: Score and Reaction from 2017 Australian Open

Roger Federer advanced to the quarter-finals of the 2017 Australian Open on Sunday after coming back from a set down to defeat Kei Nishikori 6-7 (4), 6-4, 6-1, 4-6, 6-3 in a five-set thriller in Melbourne.

The world No. 17 appeared to be on his way out of the competition after a slow start to Sunday's test saw him trail the opening set 5-1 at one point, but he fought back with ferocity to snatch his place in the last eight.

Federer will face Mischa Zverev in the quarter-finals of this year's Australian Open after the German shocked world No. 1 Andy Murray earlier on Sunday morning.

The Rod Laver Arena erupted after Federer completed the fight back against stiff opposition following a poor push off the line, and the Australian Open captured the moment he clinched his place in the next round:

Federer opened Sunday's bout in capitulating fashion, surrendering his first two serves as Nishikori quickly amassed a 4-0 lead in the opening set and gave the impression their duel might be over sooner than expected.

As far as slow starts go, Federer could hardly have hoped for a worse beginning, but he soon made up for that slump with a five-game spree from 5-1 down, per the New York Times' Ben Rothenberg:

The Swiss broke Nishikori's serve on two occasions amid that strike back from apparent peril, and though he managed to somehow tie level at six games apiece, he was unable to make his revival count in the tiebreak.

Tennis writer Chris Goldsmith noted it was a draining comeback made in vein for Federer as Nishikori served his way to a 7-4 victory in the tiebreak, but the Swiss had a chance to draw on his spirited display as inspiration:

And it was clear the Swiss was properly warmed up for the meeting by the time the second set tipped off, as he proceeded to enjoy a much more evenly weighted experience inside the Rod Laver Arena.

He won a magnificent 95 percent of points on his first serve in the second set, per the IBM SlamTracker, but it was on Nishikori's serve at three game apiece that Federer turned on the power to clinch a crucial break and lead 4-3.

Nishikori was a tad overzealous in some of his return attempts, and Federer did a fine job of pinning his enemy to the baseline, making returns difficult to pull off en route to a 6-4 win for the Swiss.

That being said, there were still holes in the Swiss star's game, as Christopher Clarey of the New York Times detailed unforced errors were one statistic still running in Federer's favour:

If Nishikori was complacent in allowing Federer back into the first set after leading 5-2, Federer showed much more resilience in building—and preserving—an almost identical advantage in a terribly one-sided third set.

The Japanese contender led 1-0 before suffering three successive breaks and failing to force even one deuce scoreline on his own serve, with a sharp change-in-power shift required if he was to have a chance at turning the result:

He gathered enough to record two crucial holds at serve at 1-2 down in the fourth game before clinching the first break of the fourth set to race 3-2 ahead. Federer learned his lessons and was much more dominant in his remaining services, failing to lose a point in either, although Nishikori saw out the remainder to win 6-4 and level the match at two sets each.

Stamina also came to play its part during the match's latter stages, and Nishikori took advantage of a medical break in order to receive treatment on a hip injury after falling 3-0 down in a climactic fifth and final set.

Nishikori looked more spry around the court after seeing to his injury concern, but there was little stopping Federer on his own serve. He proceeded to build that three-game advantage into a 5-3 cushion and would serve for the win.

While his opponent continued to pull off smart shots in decent quantity, the Rod Laver Arena roared Federer onto yet another quarter-finals appearance after serving to love in whirlwind time:

Federer will face Zverev in the quarter-finals of the 2017 Australian Open after the German combatant beat top seed Murray 7-5, 5-7, 6-2, 6-4 in Melbourne on Sunday.

Both players will undoubtedly fancy their chances of progressing more now that the defending champion is out of the running, but Federer in particular can afford to dream of a renaissance triumph Down Under in 2017.