British teens Felix Gill, Jack Pinnington Jones and Arthur Fery overcame big differences in the rankings to win their first matches in Wimbledon qualifying.
Gill, 19, defeated Serbian Danilo Petrovic, ranked 823 places above him, 7-5 7-6 (8-6).
Fery, also 19, defeated 29th seed Indian Prajnesh Gunneswaran, 891 places higher, 6-1 7-6 (7-5).
Pinnington Jones, 18, overcame a 983-place deficit in a 6-4 6-3 win over Brazilian Joao Menezes.
They are joined in the second round by Anton Matusevich, who came from behind to beat 16-year-old William Jansen, 4-6 6-0 6-4 in an all-British encounter.
But his compatriots Ryan Peniston, Aidan McHugh and Stuart Parker have all been beaten.
In the women’s qualifying event, world number 459 Tara Moore defeated Mexican world number 131 Renata Zarazua 7-6 (7-3) 6-2.
Britons Eden Silva and Eva Shaw are set to play their first round matches later on Tuesday, after the rain washed away the first day of play on Monday.
There are three qualifying rounds for Wimbledon, with the turf Grand Slam starting on Monday.