Angelique Kerber has called for the final pair of round-robin matches at the WTA Finals to be played simultaneously, saying she found it difficult to fully concentrate on her match.

Kerber needed to win at least one set to advance to the semifinals after Garbine Muguruza’s three-set win over Petra Kvitova earlier in the day. But the German lost to Lucie Safarova in straight sets, giving her a 1-2 overall record, winning two sets and losing six. Kerber, Kvitova, and Safarova each ended the round-robin stage of the tournament with 1-2 match records, with Kvitova going through because she was 3-7 in sets won.

"I think it's fairer like in football if you play in the same time," said Kerber, referring to World Cup soccer matches. "I was actually trying to be in my tunnel and just focusing on my match. I told everybody I'm not counting. I will go out and play my match. They were counting. 'Okay, she won one set, now you must win just one set.'"

The WTA Finals are held at a one-court stadium at Singapore, meaning that matches cannot be played at the same time.

Kerber admitted that she did not handle the pressure well.

"From the first point I couldn't find my rhythm," she said. "I was tight and I was not playing my tennis. Lucie played a good match for sure, but for sure it was not my best match today."

Safarova, meanwhile, was happy to have helped send her friend and fellow Czech Kvitova through to the weekend. The two will play together in the Fed Cup final next week. "That's teamwork," said Safarova. "I am happy for Petra that she went through to the semis and I am happy for my win today as well."