Britain’s Katie Boulter reached the Australian Open second round despite forgetting the rules in the tournament’s first final-set tie-break.
Boulter, 22, thought she had won after reaching seven in the decider against Russian 2015 semi-finalist Ekaterina Makarova and celebrated accordingly.
“I forgot it was first to 10,” said the British number two, who composed herself to win 6-0 4-6 7-6 (10-6).
But fellow Britons Harriet Dart and Heather Watson suffered heavy losses.
Dart, 22, fell to a chastening 6-0 6-0 defeat by five-time Grand Slam champion Maria Sharapova as they opened the tournament on Rod Laver Arena.
Watson, 26, fared little better, losing 6-1 6-2 to Croatian 32nd seed Petra Martic in hot conditions that she said had made her feel light-headed.
Boulter will face another tough test in the second round when she plays Belarussian 11th seed Aryna Sabalenka on Wednesday.