Signs of stress surrounded Rafael Nadal everywhere he looked: Kei Nishikori’s scalding groundstrokes, a blister on his palm, a blown-out shoelace on his Nike, a second-set deficit, a coaching violation warning, and time violations. The top seed had his hands full on multiple fronts.

Nadal showed he was up to the multi-tasking test, defeating Nishikori, 7-6 (3), 7-5, 7-6 (3) in an entertaining three-hour and 17-minute adventure. The world No. 1 extends his career record against the 17th-ranked Japanese to 6-0, and has won their last 14 sets.

Bursting out of the blocks, Nadal broke to open the contest and won eight of the first 10 points in building a 2-0 lead. In the fourth game, he lost the range on his backhand as Nishikori began striking with greater authority. Nadal netted a flat backhand before sailing to topspin backhands long to drop serve for the first time in the tournament as Nishikori leveled for 2-all.

Smacking his backhand down the line to damaging effect, Nishikori dug out of a triple break-point deficit to hold for 4-3. Three points into the first-set tiebreaker, chair umpire Eva Asderaki hit Nadal with a coaching violation warning. Rafa smiled it off (apparently replying “It doesn’t matter,” according to ESPN’s Brad Gilbert, who was sitting courtside), but it deepened his defiance as he drew two errors for a 4-2 lead. Nishikori launched himself airborne for a dazzling backhand down the line, but by the time he landed, Nadal was already knifing a sliding slice backhand winner cross-court for 6-2. He thumped a serve winner to close the 65-minute opening set.

In the past, Nishikori, who is listed at 150 pounds, has wilted from the substantial strength disadvantage he faces against Rafa. Not this time. With new coach Michael Chang watching intently, Nishikori timed the ball beautifully, struck his drives on the rise, and frequently forced Nadal into scrambling replies. Running down a drop volley, Nishikori scraped a desperate reply, and with a wide-open expanse of court in front of him, Nadal nudged an easy overhead wide as Nishikori broke for a second time to take a 3-2 second-set lead.

Stepping into the court, Nishikori won 61 percent of the points played on Nadal’s second serve, but couldn’t make the break stand as Nadal whipped a forehand winner down the line to break back for 4-all. Serving to extend the set at 5-6, Nishikori paid the price for one of his poorest service games as Nadal drilled a running forehand winner down the line to take a two-set lead at the two hour and six-minute mark.

Surging out to a 4-1 lead in the third set, Nadal seemed in complete command, but Nishikori broke back for 3-4. When Asderaki hit Nadal with another time violation at 4-all, deuce, he lost a first serve; Nishikori proceeded to pounce on the second and eventually broke for 5-4. Angered by the infraction, a fired-up Nadal broke back for 5-all.

Turning up his serve in the tiebreaker, Nadal hit two of his 12 aces to seize a 4-1 lead before finally pulling the plug on the electrifying Nishikori to reach the Australian Open quarterfinals for the seventh straight time, where he will face Grigor Dimitrov.

“[Nishikori is] a fantastic player, he’s able to hit the ball very early and that’s very difficult,” Nadal told Jim Courier after the match. “The ball was coming back very, very quick and it was difficult for me to take the position from inside the court. I was close to losing every set… I had to run a lot today but I am happy my legs stayed okay.”