For the first time on the ATP World Tour, Kei Nishikori and John Isner, respective national No. 1s, will meet to determine who will advance to the following round of the tournament. Following impressive fourth round wins, the two will look to determine who will advance to the final four of the tournament.

In one of his easiest matches so far this season, Kei Nishikori cruised into the quarter-final round in Miami following a straight sets victory over David Goffin. He beat the Belgian 6-1, 6-2 to secure his spot in the following round. Nishikori struck five aces, won 74% of his first service points and saved three break points to close out the match in 68 minutes. Another win for the Japanese No. 1 would ensure that he matches his best performance at the event from last season.

“I don’t think it usually happens, but I have been playing well, so everything is going well,” Nishikori said of his early success. “My serve, my return, my strokes–I feel a lot of confidence, playing good.”

Nishikori’s upcoming opponent, John Isner, barely edged the higher seeded Canadian Milos Raonic to advance to the quarter-final round. It was a serve dominated encounter, as expected, and Isner managed to hit 25 aces against Raonic’s 12 to close out the match 6-7(3), 7-6(6), 7-6(5) in two hours and 43 minutes. This is the first time that the American reaches the semi-final stage of this particular Masters 1000 event.

This marks the first time that Nishikori and Isner will meet on the professional tour and makes for a difficult encounter to predict. While the Japanese No. 1 is yet to find his peak form from last season, he should hold the edge against the big-serving American. However, Isner’s win against Raonic was an encouraging sign for his potential to advance to the semi-final round in Miami.

Prediction: Kei Nishikori in Three Sets