Cavaday raced through the first set against Craybas
Naomi Cavaday scored a notable win on the opening day of the DFS Classic by beating 14th seed Jill Craybas.
Kent's British number five saw off the experienced American 6-0 6-4 in under an hour to reach the second round.
She was joined by Hull's Katie O'Brien who beat Alla Kudryavtseva of Russia 6-0 3-6 7-6 (7-2) in Birmingham.
Also going through at Edgbaston Priory was Melanie South, who came out on top in an all-British clash with Anna Fitzpatrick, winning 6-4 6-4.
But former British number one Elena Baltacha ran out of steam against Russian 15th seed Ekaterina Makarova, losing 7-5 7-6 (7-1) in just under two hours.
Cavaday, 19, who next faces India's Sunitha Rao, was as delighted by her win over Craybas.
"She's been around a long time but I had nothing to lose," she said. "I just went out there and had a swing. I really enjoyed it. I got off to a great start and kept it going."
O'Brien's next opponent will be Russian qualifier Yaroslava Shvedova, who caused the biggest upset on the opening day with a 6-3 6-1 defeat of Ukrainian 10th seed Akgul Amanmuradova.
Baltacha, 24, had beaten Makaova, ranked 62nd in the world, in their previous two matches but wilted in the midday heat.
There was also a first-round defeat for Amanda Elliott, who had come through two tough qualifying matches to gain a place in the main draw.
She came from a set down to beat both Abigail Spears and grasscourt specialist Brenda Schultz-McCarthy, and threatened to do the same against French 13th seed Aravane Rezai.
Elliott lost the first set but hit back to level, and was a break up in the third. She also had a matchpoint in the deciding tie-break before going down 6-3 2-6 7-6 (8-6).
"I feel I gave it everything I possibly could," said the Hertforshire 18-year-old.
"At the moment, I feel a bit gutted but I've won two tough qualifying matches and had a match point against a really good player so there are a lot of positives."