Casper Ruud was supposed to play a challenger event in Japan this week. Then he got a wildcard into the Rio Open, changed his plans, and might just have changed his career too.

Ruud, the son of former top 50 player Christian Ruud, reached the semifinals of the ATP 500 event, scoring the first ATP wins of his career. "It's been amazing," he said in a courtside interview following his quarterfinal victory. "It's been kind of a breakthrough week.

"Three weeks ago I wasn't supposed to be here even. I was going to be in Japan right now, playing some challenger.

"I just want to keep up my level... in the following weeks, and following tournaments."

The youngster from Norway had already enjoyed a rapid rise up the lower-ranks, going from No. 1140 to his current No. 208 in a little more than a year, and will now be in the top 150 in the rankings.

"I am the lowest-ranked player in the draw, so I'm the underdog in every match," he was quoted as saying by the ATP. "That's more comfortable for me."

He's aiming to "keep [his] feet on the ground and keep working hard," and suggested the slower clay court conditions at the tournament suited his game.

Ruud credits his father with playing an important role in his professional ambitions. "He is an essential part of my team. I don't feel any pressure that he was a professional player. In fact, it's the opposite, it has helped me a lot," he said.

It was the third ATP event of his career .