Kei Nishikori hits Diego Schwartzmann where it hurts during warm-up for Madrid Open second-round showdown

Nishikori went on to win the match 1-6 6-0 6-4 victory in two hours

Kei Nishikori in action against Diego Schwartzman (Getty)

Kei Nishikori struck an early blow ahead of his Madrid Open second-round match against Diego Schwartzman after firing a backhand shot into his opponent’s crotch during their warm-up.

The Argentine was caught off guard by the surprisingly accurate stroke as he rallied with the world No 8.

Nishikori, who is competing in his first event since suffering from a wrist injury that saw him miss the Monte Carlo Masters and pull out of the Barcelona Open, was quick to apologise to his opponent before securing a 1-6 6-0 6-4 victory in their second-round showdown.

Schwartzman, clearly eyeing revenge, hit the ground running to claim the first set 6-1 but Nishikori hit back as he went on to produce some of his best tennis to subdue the baseline power of his opponent.

The Japenese secured a 6-0 victory in the next set and went on to seal the deal with a 6-4 win in the third.

Nishikori, the 2014 runner-up, drew on his reserves to come through a 22-point first service game and led 3-1 in the deciding set, before Schwartzman made a comeback.

The 27-year-old, who had defeated Schwartzman over three sets at the Argentina Open in February, could not convert four match point opportunities at 5-3, but one game later he secured his place in the third round with a backhand winner down the line.

“It was a very tough one,” said Nishikori after the game. “He’s obviously playing very well, very solid from baseline. He was very aggressive in the first set. But in the second set, I started grinding a little more and played a little smarter.

“I have to say I was a little bit lucky. There was a couple of net cords and balls hitting the lines. Sometimes, I need some luck to win. I'm very happy with my tennis in the second and third sets.”

No mention of that earlier crotch-shot, though.