CNN  — 

Rafael Nadal called it one of the more scary moments he’s had on the tennis court.

The world No. 1 was en route to a straight-sets win against Argentina’s Federico Delbonis, leading 4-1 in the third set of their second-round match Thursday.

But on a return of serve, a scorching forehand from Nadal hit a ball girl on the head.

There was an audible gasp from the crowd. Nadal grimaced.

“For her, probably it was not a good moment,” the Spaniard said on court after the match. “I was so scared for her, honestly.”

The girl gave him a thumbs up, but a still-concerned Nadal and Delbonis both went over to her to make sure that she was OK. Nadal lifted the girl’s hat, gave her a kiss on the cheek and patted her on the head, drawing cheers from the crowd.

Nadal checks to see if the ball kid is OK after she was struck by a ball.

Nadal went on to win the match 6-3 7-6 (4) 6-1. He next will face fellow Spaniard and No. 27 seed Pablo Carreno Busta.

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After the win, Nadal went up to the ball girl again and handed her his headband.

“She’s a super brave girl,” Nadal said.

The Australian Open is the only major Nadal has won just once, back in 2009.