Nadal struggled past Belarusian qualifier Ivashka 3-6, 6-2, 6-4 yesterday to reach the Round of 16 for the 16th time in Barcelona. Nishikori meanwhile played a marathon match too, outlasting Cristian Garin in his second round match on Wednesday.
Let's take a look at three crucial factors that might determine the outcome of today’s match:
#1 How well Rafael Nadal can attack Kei Nishikori’s forehand
The natural angle of Rafael Nadal’s forehand takes the ball towards Kei Nishikori’s backhand. But the prodigious topspin generated by Nadal's forehand might not trouble Nishikori much, as the latter has a very good backhand which he can take on the rise.
The Japanese might also use the backhand down the line liberally, which could test Nadal’s own backhand.
Therefore, the Spaniard could look to play the down-the-line and inside-out forehands more often to move the ball to Nishikori’s weaker forehand.
#2 Whether Kei Nishikori can capitalize on a possible shaky start by Rafael Nadal
Rafael Nadal has been having shaky starts on clay of late. He lost the opening set against both Andrey Rublev in Monte Carlo and Ilya Ivashka in Barcelona.
The 34-year-old had only two winners (against nine unforced errors) in the first set against Ivashka, which allowed the latter to dictate terms from the baseline. Nadal did not play aggressively enough, and it was primarily Ivashka who was going for winners with his forehand.
Kei Nishikori would have to capitalize on any such shortcomings from Nadal on Thursday, and try to start with a bang. Although Nadal has come back strongly after forgettable opening-set displays in each of his last two matches, he cannot afford to let the experienced Nishikori gain an upper hand from the get-go.
#3 Whether both players can improve their serving numbers
Rafael Nadal’s serve hasn't been too impressive since the beginning of the claycourt season this year. His first-serve ratio was below 50% in the opening set against Ivashka, and although it improved thereafter, the shot as a whole still needs a lot of work.
If Nadal doesn't get enough first serves in, Nishikori will look to take full advantage of his second serve.
However, it needs to be mentioned in this context that Nishikori himself does not have a very strong serve. The Japanese has been broken quite a few times in his first two matches at Barcelona, and he has historically struggled to close on his serve.
Nadal will definitely keep that in mind and will try to get an early break in every set, which would give him a strong grip on the proceedings from the beginning.