Simona Halep said her run to the US Open semi-finals was a necessary boost to a self-confessed "s*** season".

Halep, the world number two, reached the Australian Open quarter-finals in January, but her major results wavered at the French Open (second round) and Wimbledon (first round) before another deep run at Flushing Meadows.

Her loss to Flavia Pennetta on Friday was a surprise - in particular the ease of the Italian's 6-1 6-3 win - but Halep said turning around her fortunes on the big stage came as a relief.

"Of course I take positive things. I have played about 16 matches in USA after my s*** season, Roland Garros and Wimbledon," Halep said with a smile.

"So I'm happy with my results here. 

"I'm happy that I could reach semi-finals for first time in US Open. It's the best grand slam [result] this year. So I have no negatives. 

"I just want to take a rest few days and to start again to play matches, tournaments, and to be like I was here: confident and with pleasure on court."

Halep said she failed to fire mentally in her last-four clash, but claimed she had more fight than when she bowed out at Melbourne Park to Ekaterina Makarova 6-4 6-0 - the Russian won eight of the final nine games.

"I was flat. I was like in Wimbledon almost. I was flat emotionally and was very tough. I tried," the Romanian said. 

"It was better than Australian Open when I gave up during the match. Here I tried to find a way to play better, but I couldn't. So it's OK, and I have to just to go ahead."