Katie Boulter became the first Briton to reach the second round of the girls' singles at Wimbledon this year by defeating 13th seed Priscilla Hon.
The unseeded 17-year-old from Leicester beat the Australian 6-3 6-3 to set up a tie with France's Margot Yerolymos.
But there were losses for Freya Christie, Harriet Dart, Jodie Anna Burrage in the girls' and Jamie Malik to Noah Rubin in the boys' event.
Joshua Sapwell is already in the boys' second round after his win on Saturday.
Nottingham's Christie, 16, had fought back valiantly in the first set from 5-2 down to take it to a tie-break against Marketa Vondrousova, where she stormed into a 5-2 lead.
However, from there she lost five straight points to fall 7-5 to 12th seed Vondrousova, before the powerful Czech dominated the second set, winning it convincingly 6-2.
Londoner Dart, meanwhile, had resumed the day one set ahead of Anhelina Kalinina at 6-2 5-5, after rain postponed their meeting on Saturday.
The Ukrainian overwhelmed her opponent in the second-set tie-break to take the match to a final set, where both players showed their prowess and promise, breaking each other twice before Kalinina got the decisive one at 4-3, and did not look back.
Malik came on to court four straight after Dart, but struggled early on, falling 4-1 down before finally breaking Rubin, who duly broke back and won the set.
The American then got the decisive break in the seventh game of the second set and, despite saving two match points, Malik could not do the same for the third to lose 6-2 6-4.
Late on court 19, after a rain delay, Burrage took on Turkey's Ipek Soylu, who claimed the first set 6-4.
There were three consecutive breaks in the opening games of the second in favour of Soylu, before she took control, and Burrage succumbed 6-3, double faulting on the final point.