Emma Raducanu admitted she was still adapting to life on the WTA Tour after she lost comfortably to Ukrainian Marta Kostyuk in the quarter-finals of the Transylvania Open.
US Open champion Raducanu hit 41 unforced errors in Friday night’s match as Kostyuk wrapped up a 6-2 6-1 victory in less than an hour.
It was the British teenager’s second defeat in four matches since she secured her stunning victory at Flushing Meadows in September.
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"I wasn't physically feeling 100 per cent. I was quite tired and lethargic today. Sometimes you just have those days where you don't feel your best," Raducanu said.
"I knew from the morning, I knew from practice.
"I wanted to go out there on the court and try my best and see how it was going to go, maybe it would go better. But I just couldn't get it going today unfortunately.
"It's just disappointing that you have these days. It's not a nice feeling to have, but I just need to move on from it and brush it off. And then I'll be back in another tournament soon."
Raducanu did not drop a set at Flushing Meadows last month as she became the first qualifier to win a Grand Slam tournament.
She has since split with her coach, former Davis Cup player Andrew Richardson, but said the search for a new one was “going in a good direction”.
The Brit won her first WTA Tour matches this week and is scheduled to finish her year with an appearance at the Upper Austria Ladies Linz, which starts next weekend.
"I think it's just the last six months," she said. "It's been a lot of learning and I've experienced a lot in the last six months with not so much gaps.
"I'm just adapting to the fast-paced life of the tour and obviously still very new to it, so it's still going to take me some time to adjust.
"After Linz I'll probably have a week off just to reset and (be) mentally and physically fresh for the tough preseason. It's going to be my first one and from what I've heard, it's a very difficult four weeks physically."
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