(CNN) In the final tournament of her remarkable breakout season, Emma Raducanu lost in three sets at the Upper Austria Ladies Linz to Chinese qualifier Wang Xinyu.
The 18-year-old, who stunned the world of tennis by winning the US Open as a qualifier back in September, came into the tournament as the No. 1 seed and was hoping to add to her first two WTA Tour victories at last month's Transylvania Open.
Raducanu broke into the world's top 20 for the first time on Monday after reaching the quarterfinals in Romania, but was unable to get the better of the highly-rated Wang, eventually going down 6-1 6-7 7-5.
"I thought Xinyu played extremely well, especially in that first set," Raducanu, who suffered with an injury in the deciding set, told reporters. "And I'm proud of the way I fought to try to get back into the match.
"Everything was going her way and she was playing extremely well, so a lot of credit to her for keeping that level out there on the court.
"In the third set, I had a hip spasm in the first point of that game, and from there, I was just fighting to try to stay in it."
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The 20-year-old Wang is tipped to have a bright future and is on the brink of breaking into the world's top 100 for the first time.
Following the defeat, Raducanu confirmed reports that Torben Beltz will be her new coach.
The German joins Raducanu's ranks with a lofty reputation, having coached former world No. 1 Angelique Kerber to her wins at the Australian Open and US Open in 2016.
The pair will begin working together when Raducanu starts her preseason at the end of November.
"It's obviously a great privilege to be working with such an experienced coach," Raducanu said. "I'm definitely very excited to work with him throughout the preseason and into next year. Things are looking up and very positive, [I'm] excited about the work that is to come.
"Obviously, he has worked with Kerber, who is such a great player and won three slams. I think that experience definitely helps with someone as inexperienced as me," Raducanu added.
"He can help guide me through, which I feel really confident about. Also, he's a really positive, cheerful guy who brings great energy to the team, so I think that's also important when you're traveling on the road for quite a long time on the tour."