Stunned Serena Williams unsure what rest of 2016 holds

Serena Williams couldn’t get her mind off her sore left knee as she was sent reeling from the US Open semi-finals by 11th-ranked Czech Karolina Pliskova.

The 34-year-old Williams, who was gunning for a 23rd Grand Slam title that would take her past the record she shares with Steffi Graf for most in the Open Era, said “some serious left knee problems” had affected her game — as much mentally as physically.

“When you’re hampered you’re thinking of other things,” she said. “Like I was making errors that I never make, and definitely I didn’t make in this tournament in particular,” said Williams, a six-time US Open winner.

“So many simple, simple shots that I easily could have made,” she said. “I just blame that on just mentally thinking about my leg and just not thinking about the shot.”

Williams praised Pliskova’s ability to take advantage in her first Grand Slam semi-final, saying that even with the injury if the Czech had offered her any opportunity she might have been able to take it.

Williams insisted fatigue wasn’t a factor in her semi-final defeat. “I wasn’t tired from yesterday’s match,” she said. “I’m a professional player, I’ve been playing for over 20 years. If I can’t turn around after 24 hours and play again then I shouldn’t be on tour.”

She said it was too soon to say how it might affect her schedule for the rest of the year.

“Honestly, I don’t know,” Williams said.