SHENZHEN, China - Bianca Andreescu has withdrawn from the Shiseido WTA Finals Shenzhen due to a left knee problem.

The US Open champion suffered the injury when she was forced to retire from her round-robin clash with Karolina Pliskova.

Read more: Pliskova scores WTA Finals win as Andreescu retires

“I had a scan Thursday to check my knee after last night’s match and unfortunately the results show that I need to withdraw,” said Andreescu.

“It was amazing to play here in Shenzhen at the end of this incredible season. I’m very disappointed to not be able to finish the year on my terms, but I am hopeful I will have more chances to play here in the future.”

Alternate Sofia Kenin will replace Andreescu for the final round-robin match and will take the court at 6:30pm local time on Friday to face Elina Svitolina.

Read more: Alternate Reality - Sofia Kenin's waiting game

At a media conference in Shenzhen on Friday, Andreescu provided more details about her injury.

"I twisted my knee during a forehand return," said the Canadian. "I heard a crack. After that it was hard to put pressure on it. On the spot, the physio thought it was my meniscus, so she taped it up. It was really hard to bend with the taping and the pain kept getting worse, so I had to stop. I fought with what I had, but I didn't want to get it worse.

"The MRI scan just showed it didn't look good enough to play. It's very disappointing. It's the last tournament of the season. You want to go all out but stuff happens.

"You just got to take a step back. That's what I did. I think this is the best decision for me right now."

Andreescu still ends a breakthrough season with a positive outlook having qualified for and experienced her first WTA Finals.

"It's really nice to be among the best women athletes in the sport," she said. "It's an incredible event. I think it's one of the best events of the season really.

"I think it definitely gives me a lot of motivation to work hard for next year so I can come back. Now I'm going to take time off, be with my family, with my friends, recover, then start my pre-season. I'll become even stronger for 2020."

Read more: Andreescu - 'At some point an athelete has to say stop'