Svetlana Kuznetsova hacked off part of her own hair at a changeover as she beat defending champion Agnieszka Radwanska at the WTA Finals.
The 31-year-old Russian, who qualified for the event ahead of Britain's Johanna Konta, cut her ponytail with scissors at the start of the third set.
"It was bothering me a lot. When I was hitting the forehands I hit a good shot and it would hit my eye," she said.
"I thought, 'what's more important? My hair, which can grow, or the match?'"
Kuznetsova asked the umpire to supply her with a pair of scissors to carry out her impromptu haircut.